But while Adobe provides a free reader for viewing PDFs, creating PDFs yourself can be costly and confusing, even though the format is great for saving and sharing documents of almost any kind including images, Web pages, Word documents and emails. For users who want higher-end PDF creation and collaboration software, Adobe Systems Inc. offers its $450 Adobe Acrobat 8 Professional software program. But that’s pricey for most casual users. So this week I tested some inexpensive or free methods for making PDFs.

Converting documents into PDFs is simplified with Adobe’s online service (top) and Docudesk’s deskPDF program (bottom).

There are plenty of Windows programs available for download online that will help you create basic PDFs. On Windows computers, I tried three programs, starting with the $20 standard version of deskPDF from Plano, Texas-based Docudesk Corp. (www.Docudesk.com). I tested a stripped-down and less-expensive version of Adobe’s program called Create Adobe PDF Online, which works by uploading your document at www.CreatePDF.com and costs $10 monthly or $100 annually. And I also used a free program called CutePDF from Acro Software Inc. (www.CutePDF.com).

If you own a Mac, things are even simpler. Macs come out of the box with the ability to turn documents into PDFs, and I tested that function as well.

DeskPDF and CutePDF worked roughly the same way, though deskPDF costs $20 and CutePDF is free. Adobe’s less-expensive program offered a few more features than deskPDF and CutePDF, such as the ability to add password encryption to a document or to make it unprintable by others. Making PDFs on the Mac was a cinch, including options to compress or encrypt a PDF. None of these methods allowed me to add extra features to PDFs like bookmarks and hyperlinks; for that, you’ll need a more serious program.

When Microsoft’s Office 2007 program shipped early this year, many people expected that it would have the built-in ability to save documents in PDF format; it didn’t. Users can find a patch that fixes this on Microsoft’s Web site.

Apple’s operating system has long been known for the ease with which it can create PDFs using built-in tools. Put simply, any document that can be printed from a Mac can also be turned into a PDF. Users follow the normal steps necessary to print a document or Web site (usually File, Print), but can choose a button on the Print screen labeled “PDF” that converts the document.

In seconds, I turned all types of documents on my iMac into PDFs, including images in JPEG and TIF formats, emails, Word documents and Web sites. This last conversion was helpful for saving not just a view of the current screen, but the entire site from the top of the page to the bottom.

Options labeled “Compress PDF” and “Encrypt PDF” can be chosen in this Print screen. I chose Encrypt PDF and protected a PDF using a password in one quick step. The option to compress a PDF will decrease the size of an image in a document, but won’t decrease the size of a text-only document.

Two of the three Windows programs use a method similar to Apple’s, letting me send documents or Web sites into print mode and converting them into PDFs. Downloading and installing deskPDF or CutePDF adds a virtual printer driver to the computer. Rather than choosing a separate button labeled “PDF,” the conversion program is selected from a list of printers, and hitting the Print button saves the document as a PDF file. The first time I did this, I thought my document was printed rather than saved because a printer icon appeared in the bottom right-hand corner of the screen, as if the document was printing. But a screen appeared asking where I wanted to save the new PDF, and I specified a location.

Docudesk offers free 24-hour technical support with all of its deskPDF programs, even trial versions. The company also touts its $40 deskUNPDF program, which restores PDFs to Word documents for editing purposes, one of the features also found in Adobe’s $450 product.

CutePDF writer and deskPDF must be used with separately installed converter programs, but these are small and free, and their installation is prompted after each of the core programs is downloaded. Both programs are also offered in upgraded versions that cost $50 for CutePDF Pro and $30 for deskPDF Pro, enabling advanced features like hyperlinks, encryption, password protection and printing restrictions.

Adobe’s Create Adobe PDF Online program offers a few more features than the others, but feels a bit disconnected because it uploads documents to the Web for PDF conversion rather than converting documents in an installed program.

An option called Create Adobe PDF Online Printer installs a printer driver on your PC, like deskPDF and CutePDF. But this saves your PDF online forcing you to retrieve it via Adobe’s Web site, an emailed link or an emailed attachment.

After registering to use Adobe’s online conversion product, users must select the file or Web page intended for PDF conversion. Security features are optional with each document, such as requiring a password to view it or not allowing others to print it. I tried both successfully. Once converted, a document can be delivered to you via email in a link or attachment. It can also be retrieved from a Conversion History section on the site or converted directly on the site.

Most of these conversion programs are available in some free capacity. DeskPDF can be used five times free of charge in the standard and professional versions before it starts adding a watermark to each PDF, which is intrusive. Adobe’s program can be used five times for each email that you register before you must subscribe to its conversion service.

If you need to save a document in a format that has the greatest likelihood of being viewable by all of your recipients, PDFs are the way to go, and they aren’t difficult to make.

Edited by Walter S. Mossberg

• Email: MossbergSolution@wsj.com

One of the most important trends in personal technology over the past few years has been the evolution of the humble cellphone into a true handheld computer, a device able to replicate many of the key functions of a laptop. But most of these “smart phones” have had lousy software, confusing user interfaces and clumsy music, video and photo playback. And their designers have struggled to balance screen size, keyboard usability and battery life.

Now, Apple Inc., whose digital products are hailed for their design and innovation, is jumping into this smart-phone market with the iPhone, which goes on sale in a few days after months of the most frenzied hype and speculation we have ever seen for a single technology product. Even though the phone’s minimum price is a hefty $499, people are already lining up outside Apple stores to be among the first to snag one when they go on sale Friday evening.

We have been testing the iPhone for two weeks, in multiple usage scenarios, in cities across the country. Our verdict is that, despite some flaws and feature omissions, the iPhone is, on balance, a beautiful and breakthrough handheld computer. Its software, especially, sets a new bar for the smart-phone industry, and its clever finger-touch interface, which dispenses with a stylus and most buttons, works well, though it sometimes adds steps to common functions.

The Apple phone combines intelligent voice calling, and a full-blown iPod, with a beautiful new interface for music and video playback. It offers the best Web browser we have seen on a smart phone, and robust email software. And it synchronizes easily and well with both Windows and Macintosh computers using Apple’s iTunes software.

It has the largest and highest-resolution screen of any smart phone we’ve seen, and the most internal memory by far. Yet it is one of the thinnest smart phones available and offers impressive battery life, better than its key competitors claim.

The phone is thinner than many smart phones.

It feels solid and comfortable in the hand and the way it displays photos, videos and Web pages on its gorgeous screen makes other smart phones look primitive.

The iPhone’s most controversial feature, the omission of a physical keyboard in favor of a virtual keyboard on the screen, turned out in our tests to be a nonissue, despite our deep initial skepticism. After five days of use, Walt — who did most of the testing for this review — was able to type on it as quickly and accurately as he could on the Palm Treo he has used for years. This was partly because of smart software that corrects typing errors on the fly.

But the iPhone has a major drawback: the cellphone network it uses. It only works with AT&T (formerly Cingular), won’t come in models that use Verizon or Sprint and can’t use the digital cards (called SIM cards) that would allow it to run on T-Mobile’s network. So, the phone can be a poor choice unless you are in areas where AT&T’s coverage is good. It does work overseas, but only via an AT&T roaming plan.

In addition, even when you have great AT&T coverage, the iPhone can’t run on AT&T’s fastest cellular data network. Instead, it uses a pokey network called EDGE, which is far slower than the fastest networks from Verizon or Sprint that power many other smart phones. And the initial iPhone model cannot be upgraded to use the faster networks.

The iPhone compensates by being one of the few smart phones that can also use Wi-Fi wireless networks. When you have access to Wi-Fi, the iPhone flies on the Web. Not only that, but the iPhone automatically switches from EDGE to known Wi-Fi networks when it finds them, and pops up a list of new Wi-Fi networks it encounters as you move. Walt was able to log onto paid Wi-Fi networks at Starbucks and airports, and even used a free Wi-Fi network at Fenway Park in Boston to email pictures taken during a Red Sox game.

But this Wi-Fi capability doesn’t fully make up for the lack of a fast cellular data capability, because it is impractical to keep joining and dropping short-range Wi-Fi networks while taking a long walk, or riding in a cab through a city.

AT&T is offering special monthly calling plans for the iPhone, all of which include unlimited Internet and email usage. They range from $60 to $220, depending on the number of voice minutes included. In an unusual twist, iPhone buyers won’t choose their plans and activate their phones in the store. Instead, they will do so when they first connect the iPhone to the iTunes software.

Despite its simple interface, with just four rows of colorful icons on a black background, the iPhone has too many features and functions to detail completely in this space. But here’s a rundown of the key features, with pros and cons based on our testing.

Hardware: The iPhone is simply beautiful. It is thinner than the skinny Samsung BlackJack, yet almost its entire surface is covered by a huge, vivid 3.5-inch display. There’s no physical keyboard, just a single button that takes you to the home screen. The phone is about as long as the Treo 700, the BlackBerry 8800 or the BlackJack, but it’s slightly wider than the BlackJack or Treo, and heavier than the BlackBerry and BlackJack.

The display is made of a sturdy glass, not plastic, and while it did pick up smudges, it didn’t acquire a single scratch, even though it was tossed into Walt’s pocket or briefcase, or Katie’s purse, without any protective case or holster. No scratches appeared on the rest of the body either.

There are only three buttons along the edges. On the top, there’s one that puts the phone to sleep and wakes it up. And, on the left edge, there’s a volume control and a mute switch.

One downside: Some accessories for iPods may not work properly on the iPhone. The headphone jack, which supports both stereo music and phone calls, is deeply recessed, so you may need an adapter for existing headphones. And, while the iPhone uses the standard iPod port on the bottom edge, it doesn’t recognize all car adapters for playing music, only for charging. Apple is considering a software update to fix this.

Touch-screen interface: To go through long lists of emails, contacts, or songs, you just “flick” with your finger. To select items, you tap. To enlarge photos, you “pinch” them by placing two fingers on their corners and dragging them in or out. To zoom in on portions of Web pages, you double-tap with your fingers. You cannot use a stylus for any of this. In the Web browser and photo program, if you turn the phone from a vertical to a horizontal position, the image on the screen turns as well and resizes itself to fit.

In general, we found this interface, called “multi-touch,” to be effective, practical and fun. But there’s no overall search on the iPhone (except Web searching), and no quick way to move to the top or bottom of pages (except in the Web browser). The only aid is an alphabetical scale on the right in tiny type.

There’s also no way to cut, copy, or paste text.

And the lack of dedicated hardware buttons for functions like phone, email and contacts means extra taps are needed to start using features. Also, if you are playing music while doing something else, the lack of hardware playback buttons forces you to return to the iPod program to stop the music or change a song.

Keyboard: The virtual keys are large and get larger as you touch them. Software tries to guess what you’re typing, and fix errors. Overall, it works. But the error-correction system didn’t seem as clever as the one on the BlackBerry, and you have to switch to a different keyboard view to insert a period or comma, which is annoying.

Web browsing: The iPhone is the first smart phone we’ve tested with a real, computer-grade Web browser, a version of Apple’s Safari. It displays entire Web pages, in their real layouts, and allows you to zoom in quickly by either tapping or pinching with your finger. Multiple pages can be open at the same time, and you can conduct Google or Yahoo searches from a built-in search box.

Email: The iPhone can connect with most popular consumer email services, including Yahoo, Gmail, AOL, EarthLink and others. It can also handle corporate email using Microsoft’s Exchange system, if your IT department cooperates by enabling a setting on the server.

BlackBerry email services can’t be used on an iPhone, but Yahoo Mail supplies free BlackBerry-style “push” email to iPhone users. In our test, this worked fine.

Unlike most phone email software, the iPhone’s shows a preview of each message, so you don’t have to open it. And, if there is a photo attached, it shows the photo automatically, without requiring you to click on a link to see it. It can also receive and open Microsoft Word and Excel documents and Adobe PDF files. But it doesn’t allow you to edit or save these files.

Memory: The $499 base model comes with four gigabytes of memory, and the $599 model has eight gigabytes. That’s far more than on any other smart phone, but much less than on full-size iPods. Also, there’s no slot for memory-expansion cards. Our test $599 model held 1,325 songs; a dozen videos (including a full-length movie); over 100 photos; and over 100 emails, including some attachments, and still had room left over.

Battery life: Like the iPod, but unlike most cellphones, the iPhone lacks a removable battery. So you can’t carry a spare. But its battery life is excellent. In our tests, it got seven hours and 18 minutes of continuous talk time, while the Wi-Fi was on and email was constantly being fetched in the background. That’s close to Apple’s claim of a maximum of eight hours, and far exceeds the talk time claims of other smart phones, which usually top out at five and a half hours.

The interface features \”cover flow\” technology for flipping through album covers.

For continuous music playback, again with Wi-Fi on and email being fetched, we got over 22 hours, shy of Apple’s claim of up to 24 hours, but still huge. For video playback, under the same conditions, we got just under Apple’s claim of seven hours, enough to watch four average-length movies. And, for Web browsing and other Internet functions, including sending and receiving emails, viewing Google maps and YouTube videos, we got over nine hours, well above Apple’s claim of up to six hours.

In real life, of course, you will do a mix of these things, so the best gauge might be that, in our two-week test, the iPhone generally lasted all day with a typical mix of tasks.

Phone calls: The phone interface is clean and simple, but takes more taps to reach than on many other smart phones, because there are no dedicated hardware phone buttons. You also cannot just start typing a name or number, but must scroll through a list of favorites, through your recent call list, or your entire contact list. You can also use a virtual keypad.

One great phone feature is called “visual voice mail.” It shows you the names or at least the phone numbers of people who have left you voicemail, so you can quickly listen to those you want. It’s also very easy to turn the speakerphone on and off, or to establish conference calls.

Voice call quality was good, but not great. In some places, especially in weak coverage areas, there was some muffling or garbling. But most calls were perfectly audible. The iPhone can use Bluetooth wireless headsets and it comes with wired iPod-style earbuds that include a microphone.

Google maps on the iPhone.

A downside — there’s no easy way to transfer phone numbers, via AT&T, directly from an existing phone. The iPhone is meant to sync with an address book (and calendar) on a PC.

Contacts and calendars: These are pretty straightforward and work well. The calendar lacks a week view, though a list view helps fill that gap. Contacts can be gathered into groups, but the groups can’t be used as email distribution lists.

Syncing: The iPhone syncs with both Macs and Windows PCs using iTunes, which handles not only the transfer of music and video, but also photos, contacts, calendar items and browser bookmarks. In our tests, this worked well, even on a Windows Vista machine using the latest version of Outlook as the source for contacts and appointments.

iPod: The built-in iPod handles music and video perfectly, and has all the features of a regular iPod. But the interface is entirely new. The famed scroll wheel is gone, and instead finger taps and flicking move you through your collection and virtual controls appear on the screen. There’s also a version of the “cover flow” interface which allows you to select music by flipping through album covers.

Other features: There are widgets, or small programs, for accessing weather, stock prices and Google Maps, which includes route directions, but no real-time navigation. Another widget allows you to stream videos from YouTube, and yet another serves as a notepad. There’s a photo program that displays individual pictures or slideshows.

The only add-on software Apple is allowing will be Web-based programs that must be accessed through the on-board Web browser. The company says these can be made to look just like built-in programs, but the few we tried weren’t impressive.

Missing features: The iPhone is missing some features common on some competitors. There’s no instant messaging, only standard text messaging. While its two-megapixel camera took excellent pictures in our tests, it can’t record video. Its otherwise excellent Web browser can’t fully utilize some Web sites, because it doesn’t yet support Adobe’s Flash technology. Although the phone contains a complete iPod, you can’t use your songs as ringtones. There aren’t any games, nor is there any way to directly access Apple’s iTunes Music Store.

Apple says it plans to add features to the phone over time, via free downloads, and hints that some of these holes may be filled.

Expectations for the iPhone have been so high that it can’t possibly meet them all. It isn’t for the average person who just wants a cheap, small phone for calling and texting. But, despite its network limitations, the iPhone is a whole new experience and a pleasure to use.

• Email us at mossbergsolution@wsj.com. Find all our columns and videos online free at the All Things Digital Web site: http://walt.allthingsd.com

Just a couple of months ago, in this column, we proclaimed that Apple Computer’s iMac G5, then the company’s flagship Macintosh desktop computer for consumers, was the best consumer desktop PC on the market. In fact, we called it the “gold standard” of desktop PCs and said no desktop from the major makers of Windows-based computers could match it.

Last week, in a surprise move, Apple gave the iMac a brain transplant. It chose the iMac as the first Macintosh model to be converted to work on the same Intel processors used by makers of Windows PCs, rather than the PowerPC processors from IBM that have powered Macs for many years. This was serious surgery to perform on the company’s star product and launched the planned transition to Intel much sooner than originally expected.

Apple’s new Intel-powered iMac.

Apple says it changed chips because Intel’s latest processors are faster and run cooler, and allow for more flexible and creative computer designs in the future. It says the new iMac is two to three times as fast as the old one, mainly because the Intel Core Duo chip it uses packs in the equivalent of two processors.

But there’s a downside. Nearly all existing third-party software for the Mac, including major programs like Microsoft Office, will have to be rewritten to run on the Intel processor — a process that is under way but will take months to complete. Apple had to build into the new model special, invisible, translator software that allows the older programs to run on the new chip in the meantime. This translator software, however, doesn’t work with every program and can slow down the ones it does work with.

So, how did the brain transplant go? Is the new Intel iMac as good as its predecessor? Does the machine’s raw power offset the translation slowdown?

To find out, we’ve been testing an Intel-based iMac against an iMac G5 only about a month old. The two machines look identical and sport nearly identical features. The major differences are hidden under the hood.

For days, we ran a wide variety of software on the two iMacs, and performed all of the common tasks mainstream consumers do — surfing the Web, emailing, instant messaging, word processing, using spreadsheets, editing photos, playing music, managing personal finances, playing simple games.

Our verdict: The brain transplant was a success. The two machines behaved almost identically in our tests. Compatibility is excellent. The new model easily handled all the major consumer software we threw at it. We never noticed the translator software, called Rosetta, and any slowdowns it imposed were so slight as to be indiscernible.

The new model was actually a little faster at a few of the tasks we tried, but nothing like the two to three times as fast that Apple claims. A mainstream user who didn’t know what was under the hood couldn’t tell the difference between them, even after using them for hours. It appears that the faster chip roughly balances out the translation effect.

So, if the new model works only about as well as the old one, what’s the advantage for consumers? Well, the slight, scattered, speed gains we saw should grow greater over time, as Apple and third-party software makers tweak their applications to take full advantage of the dual-core Intel chip. A year from now, an Intel iMac purchased today will likely be notably faster, if you update your software to newer versions.

But, even now, this is a terrific computer. It’s still the best consumer desktop on the market. It still runs crisply, still is free of viruses and spyware, still has the best operating system and the best built-in software of any desktop we’ve tested. Given how smoothly the new machine works, and how likely it is to get even better, we would prefer it today over the iMac G5, which Apple is still selling for the same price until inventories are gone. The G5 is still a fine machine, but the Intel model has a brighter future, and, based on our tests, it seems ready to go today.

There are a couple of caveats about our results. We tested only common consumer software and tasks, not heavy-duty or professional applications, like Adobe Photoshop, or professional music and video programs, which tend to stress the processor. Some of these nonconsumer products won’t work right until they are rewritten.

Also, there are two drawbacks to the Intel-based iMac that we judged relatively unimportant to most users, but which could be crucial to some. It can’t run old, pre-2001 Mac programs that were written for the old Mac operating system, called “Classic.” And, even though it now uses the same processors that Windows machines do, the new iMac can’t run Virtual PC, the Microsoft program that allows Macs to run Windows software. Microsoft is rewriting Virtual PC for the new Macs but won’t be done until 2007. Some other company may bring out a way to run Windows stuff on the new Mac sooner than that. But, for now, it can’t run Windows programs.

On the other hand, the new iMac has a few advantages. It has a faster video card than the old model and a digital video connector rather than an analog connector.

Doom 3, a non-Apple program, ran well on the new iMac.

From the outside, the two machines are twins. Apple was careful to keep the same physical design, a beautiful white flat-panel monitor with the entire guts of the computer stashed behind the screen in an amazingly thin space. Both have a built-in camera and microphone. The user interface and software features are also identical. Both models run the same excellent Mac OS X operating system. And both also include Front Row, the special interface that allows you to view photos and videos, and play music, from across a room using a small, included remote control.

Even the price of the new model is the same — $1,299 for a version with a 17-inch screen and $1,699 for one with a 20-inch screen.

For our tests, we copied all the third-party software and files from our iMac G5 to the Intel iMac, so the machines were configured comparably. Both had the same amount of memory, the same DVD drives and the same Internet connections.

We ran a mix of Apple and third-party software. We weren’t surprised that all the Apple programs, like iTunes and iPhoto and the Safari Web browser, ran perfectly and swiftly. Apple has already rewritten them for the Intel chip.

But we were pleasantly surprised by the performance of non-Apple programs. We tested Microsoft Office, Adobe Reader, the Firefox Web browser, Skype, Google Earth, Quicken, the Eudora email program, Doom 3, Kodak EasyShare and others — none of which had been rewritten. All launched quickly and ran smoothly and well.

We did find one program that wouldn’t run at all on the Intel iMac: AOL for Mac OSX. But AOL’s main features can all now be accessed from its Web site, so you don’t need this software in most cases.

Web pages loaded swiftly on the new iMac, though not markedly faster than on the old model. We changed the font on a thousand-word document in Microsoft Word and saw no lag at all. We created a chart in Microsoft Excel, and it appeared almost instantly. Email worked indistinguishably well.

This column was written in Word on the Intel iMac, and there were no glitches or hitches or hang-ups of any kind.

On four of our test tasks, the new model outperformed the old one significantly — all in Apple software that had been rewritten for the new chip. It was 15% faster at importing music from a CD, using iTunes. It was 42% faster at converting a video clip from one format to another, using Apple’s QuickTime program. It was 44% faster at importing nine large digital photos into iPhoto. And it was 24% faster at duplicating a huge folder filled with more than 27,000 files occupying more than 12 gigabytes of space.

Why didn’t our results support Apple’s claim of a two to three times speed gain? Like most computer companies, Apple bases such claims on special, complicated benchmark software that doesn’t necessarily match up with the kinds of mainstream consumer tasks we tested.

The bottom line: Apple’s iMac, with its new Intel processor, is still the gold standard of consumer desktop PCs. And it stands to get better over time.

• Email: MossbergSolution@wsj.com.

The software that comes with digital cameras typically isn’t very good, so it probably isn’t much help. And any photo program that came bundled with your PC, if you can find it, is also very likely of inferior quality.

Luckily, there are some good photo-organizing programs on the market, which cost little or are even free. These programs differ from traditional photo-editing software like Adobe’s Photoshop. They place less emphasis on tweaking and perfecting each picture, focusing instead on organizing your hundreds or thousands of photos and helping you share them with others. They do have basic editing tools, but they are mainly designed to help you manage your digital-photo collection.

Picasa version 2

Two of the best photo organizers have just been updated, and I have been testing them on my collection of more than 10,000 digital photos. One is Picasa 2, which runs only on Windows and is now a free offering from Google, which purchased Picasa last year. The other is Apple Computer’s iPhoto 5, which runs only on the Macintosh. It comes free on every new Mac. Existing Mac owners can buy it as part of the excellent $79 iLife suite, which also includes programs for organizing and editing music and videos, and for authoring DVDs.

Both programs are packed with good features and have been significantly upgraded in their new versions. But iPhoto is the better of the two — mainly because, unlike Picasa and most other competitors, it totally frees users from understanding the computer’s file-and-folder system. With iPhoto you can organize your photos in any way you choose, regardless of where the underlying picture files are stored on the computer. This makes iPhoto much easier to use than Picasa, or any other photo organizing program I have tested.

The key feature in iPhoto is something called the virtual album. With a few clicks of the mouse, you can move any group of photos — no matter what their subject, date or location on the hard disk — into an album you create on the fly. Any photo can appear in an unlimited number of these albums, without physically moving the file from its location on the hard disk or making any extra copies of the photos.

So, for instance, a picture of your daughter Marissa on vacation in Rhode Island could appear in folders labeled “Marissa,” “Vacations” and “Rhode Island.” This is similar to the way you can create multiple play lists in a music program like iTunes or Windows Media Player.

iPhoto version 5

Picasa, on the other hand, is largely hard-wired to the file system on your hard disk. Pictures appear in the file folders in which they are stored on the hard disk. This means you have to be good at setting up folders and naming them. There is a half-hearted effort at virtual albums in the new version of Picasa, which I’ll explain below. But it isn’t nearly as simple as the iPhoto system.

Like the original version, Picasa 2 is an attractive and speedy piece of software. It presents your photos as thumbnails in a large well at the right of the screen, and shows the hard disk’s folder organization in a list at the left. If you click on any of the photo thumbnails you are presented with options for sharing the photos, such as printing them, e-mailing them, or adding them to a Web page or blog. If you double-click on a thumbnail, you enter a slick, improved editing mode that allows you to tweak them in a wide variety of ways.

The editing system is the main new feature of Picasa 2, and it’s very good. The editing options are organized into categories called Basic Fixes, Tuning and Effects. In Basic Fixes, a button called “I’m Feeling Lucky” (a term borrowed from new parent Google) does an automatic enhancement of the picture. But you can also automatically fix contrast and color. And there’s a cool “fill light” feature that can eliminate shadows without washing out the whole image. There’s also an excellent feature that straightens a crooked picture.

The Tuning section offers control over highlights and shadows, and the Effects section has a raft of excellent features, including a “warmify” button that warms up the colors and a “glow” button that creates a sort of muted halo effect.

Picasa 2 also has a nice option for creating CDs of your photos, with slide shows included, and for backing up photos to CD or DVD.

In the original Picasa, you were stuck organizing your pictures by the hard disk’s file folders. That’s still the main organizing principle, but now you can rename the folders and move pictures among them right from within Picasa. And you can sort of create virtual albums, in a clumsy process called labeling. You first click on a picture and assign a label to it. Then you click on any other pictures to which you want to append the same label. These then appear on the folder panel in a section called “Labels.” Photos can appear in multiple labels. But the system is far slower and more awkward than in iPhoto, and each group of labeled photos gets tagged with a single date, no matter when they were actually taken.

Apple’s iPhoto is also attractive, with the same basic layout as Picasa — a library well of thumbnails to the right and a list of albums on the left. Only the albums on the left are all virtual. You don’t need to know a thing about the organization of your hard disk to use iPhoto. In the new version 5, in fact, Apple has beefed up the virtual-album system.

Now, you can create “smart albums” in iPhoto. These albums automatically collect any pictures that meet criteria you specify, such as pictures taken within a certain date range, or those with certain words in their titles. You can also now create uber-folders that can contain multiple albums, and you can save slide shows along with virtual albums on the left-hand pane.

The new iPhoto also has a much improved system for designing and ordering printed, bound books of your photos — something Picasa lacks entirely. You could always make these books in iPhoto, but now the process is simpler and there are more layouts to choose from, with more sizes and types of books.

However, iPhoto’s system for ordering mail-order prints works only with Kodak, while Picasa offers multiple vendors.

Version 5 of iPhoto also now organizes video clips as well as still photos (Picasa does this too). And, like Picasa, it can handle digital pictures in the uncompressed “RAW” format favored by photo enthusiasts. It has also added a method for finding photos by date — something competitors, including Picasa, already had.

Apple has also beefed up iPhoto’s editing functions. In addition to automatic fixes, Apple has built in a new translucent control panel that gives you manual control over brightness, contrast, saturation and other aspects of the image. Like Picasa, iPhoto now has an easy way to straighten crooked pictures. But it has many fewer editing and enhancement options than Picasa does.

And iPhoto is tightly integrated with other programs in the iLife suite. For instance, you can select play lists from the iTunes music program to enhance your slide shows without even opening iTunes. And you can send virtual albums to the iDVD authoring program for burning onto a DVD. You can easily burn an album to CD, but iPhoto lacks an automated backup feature such as Picasa’s.

If you have a Windows PC, Picasa is a decent choice, as long as you understand and maintain a good system of folders on the hard disk. But Mac owners have a better overall photo organizer in iPhoto.

With reporting by Katherine Boehret

Write to Walter S. Mossberg at mossberg@wsj.com