Tubes installs a program on the desktop (right) into which files can be dragged and shared using automatic synchronization.

This week, I tested another product in the long line of programs that uses automatic synchronization to simplify the process of sharing large files by giving you the ability to change files and privacy options at any time. It’s called Tubes (www.tubesnow.com) from Tubes Networks and it takes its name from the pneumatic vacuum-tube system commonly used in bank drive-throughs that motivated me to join my Mom on visits to the bank as a kid. Mom would pull up and a container would whoosh over through a tube to arrive beside the car window; after a quick exchange it returned with her deposit slip and a lollipop for me.

Tubes aims to work with the same sort of magic. Once installed, its desktop application stays opened on your computer as a place where “tubes” are made for sending files. Any type of file can be dragged, dropped and sent off to share with other people using these virtual tubes. As soon as you release data into a tube, a whoosh sounds (like that of the vacuum tube) and your files are encrypted and uploaded to the Tubes server.

Invited guests view your tube’s data in its full, uncompressed format. The owner of the tube always has the final say on what is shared with whom, and changes made to tubes on your hard drive are detected instantly via automatic synchronization, guaranteeing viewers will always see the latest version of the tube. Shared tubes are also accessible via the Web, saving viewers from downloading the Tubes desktop program.

Other products like Sharpcast (www.sharpcast.com) and Pando (www.pando.com) also offer ways to share large digital files; Sharpcast uses synchronization similar to that of Tubes — it all happens behind the scenes without any work on the user’s part.

Tubes is available in a free version that provides a gigabyte of storage, or in paid versions with five, 10 and 20 gigabytes of storage for $6, $11 or $21, respectively.

Most of the time, Tubes worked well for me when I installed it on two Windows machines, one running XP and one running Vista. Tubes’ smart use of an already familiar process — dragging and dropping — gives you the impression that you already know how to use it and makes sharing files seem easy. I started dragging all sorts of files into tubes that I created, naming them and labeling them with a representative icon (one of 10 offered by Tubes or one of my own images).

For all its usefulness, Tubes certainly has room for improvement. For now, there isn’t a Mac version of the program, and when friends and I tried accessing shared tubes using a Mac Web browser, the results were inconsistent and sometimes didn’t work at all. Windows Vista had its own issues. After installing Tubes on my Vista laptop, an error message labeled “invalid argument” made me feel like a member of the debate team. And I couldn’t see thumbnail images of photos in my tubes using Vista, though I could on Windows XP.

Today, Tubes is releasing an updated version of its program that aims to improve the usability and look of the product, including refining the processes of sharing tubes and looking at tubes via the Web.

Before sharing tubes, I adjusted the permissions granted to each guest by labeling them as a Reader, Author or Editor; only the Owner can invite others to view a tube. But these labels can get confusing. More than once, I granted guests the highest level of permission, which is Editor, allowing them to make changes to the files in my tube, only for the guest to be asked for his registered Tubes email and password, which an invited guest shouldn’t need.

The Tubes experience was best when the recipient of my Tubes invitations had the application installed on his or her desktop.

After installing Tubes on a computer at work, I installed it on my home PC and easily auto-synched tubes that I created at work onto my home PC — a big plus.

Tubes incorporates the Web by assigning a unique URL to every file in every tube, and every tube automatically generates its own Web site, or “tubeSite,” as it’s called. Individual URLs for each file can be found by right clicking on a file and selecting an option to copy the URL into an email or browser. I copied the URL of a shared MP3 audio file and pasted it into my browser; it played a Fountains of Wayne song with no problem. But sharing these URLs with others is only possible if the owner gives permission.

Comments about tubes can be made in the “tubeBlog” — accessible through any tube in the application or online. I created a tubeBlog for a tube with photos from one of my vacations, adding descriptions and comments to specific photos. Others, with my permission, could do the same, using the photos from the tube or just leaving comments.

A friend used Tubes to share photos with me while vacationing in Italy and Amsterdam. I added my own travel photos and an itinerary made in Microsoft Word to his tube and changed the tube’s title; these alterations synched instantly.

Even if you aren’t online, you can access tubes or make changes to them by dragging files in or taking them out; updates are made automatically the next time your computer connects to the Web.

Tubes is off to a good start, but it needs to improve its system to make permission levels more understandable for tube owners and those invited to see a shared tube. With a few improvements, Tubes could be a product that I’ll continue using on Windows computers long after this column.

Email mossbergsolution@wsj.com

Write to Katherine Boehret at katie.boehret@wsj.com

How many times have you wanted to email a large attachment — like a bunch of digital photos, an album of songs, or a hefty video — but didn’t do so because it exceeded your email provider’s, or the recipient’s, limits on attachment size, or because it might max out the recipient’s mailbox?

This frustration is growing increasingly common as better digital cameras produce bigger photos and large video clips, and digital music becomes more widespread. Computer hard disks have grown nicely to accommodate these files, but limits on the size of email messages haven’t. And, even if you could send such large attachments, it can take forever to send them via email, partly because broadband upload speeds lag far behind download speeds.

Instead of suffering the frustration of a bounced email, many folks have resorted to Web-based services like Shutterfly or Kodak EasyShare Gallery or YouTube.com or Google Video for sharing digital photos and videos. They upload the files to these sites, then send links to their friends and family. But this method has major drawbacks. The recipients don’t get the full-size files on their own computers, and sometimes must register with the sites to view your material.

This week, we tested a new, free, application called Pando that aims to solve this problem without requiring you to use an intermediary Web site. Pando lets you email huge attachments — up to one gigabyte each — to anyone, without breaching email size limits, or clogging anyone’s inbox. It comes in versions for both Windows and Macintosh computers, available for downloading at www.pando.com.

It sounded fishy to us, too, but Pando, from Pando Networks Inc., performed really well in our tests — even in its current “beta,” or trial, stage. It’s simple, fast, and effective, and it solves the large-attachment problem.

Pando works by merging the mechanism of email with its own small program and a modified version of BitTorrent, a back-end file-transfer system best known until now for speeding up the downloading of large, unauthorized files, like pirated movies.

Here’s how you use Pando. First, you download and install the small Pando program. Then, you select the files you want to send. These can be any type of files you want, or even whole folders of files. Then, still using the Pando software, you type in the addresses of the recipients, the subject, and a message. The software then does three things: it creates a Pando Package, a small special file that instructs the recipient’s computer on how to fetch the files; it sends an email containing that package file, plus any text you want; and it uploads the files to a Pando server.

On the recipient’s end, an email is received in his or her normal email program containing the Pando Package as a tiny attachment (one huge 94 megabyte attachment we sent required only a 22-kilobyte attachment). The recipient just opens the Pando Package attachment, and it in turn launches the Pando software, which then downloads the files or folders you sent. The first time the recipient receives a Pando email, he or she will have to download and install the Pando software. There’s a link in the email to the download site.

Once downloaded onto the receiver’s computer, all Pando files can be found in a special folder that Pando automatically creates. In Windows, it’s called My Pando Packages and is in My Documents. On the Mac, it’s called Pando Packages and is in the home folder. The files are also listed in the handy Received list in the Pando software.

As a bonus, Pando can sometimes transmit these large files faster than your email program or Web browser could. That’s because it uses a modified version of the speedy BitTorrent technology.

We downloaded and installed Pando in just a few minutes. Opening the small Pando email attachment from Microsoft Outlook on Windows or Apple Mail on the Mac prompted a little Pando window to pop up, in which all sent and received files were organized. This window is simple, showing a thumbnail image and text description of each file. A list of received files shows who sent the file and when; the sent list shows to whom you sent files and when.

We started out big, sharing a 95-megabyte, high-resolution video. You must create a username and password to send using Pando, which we did, entering our email and first and last names. A simple “Send New” icon opens the email-like form, where we dragged and dropped this big video file.

No Pando Package can total more than one gigabyte, and an automatic tally shows you how large the Package is becoming as you drag and drop more files into it.

The Pando software program allows users to send large email attachments without running afoul of normal size limitations.

Another way to send files using Pando is by right-clicking on any file or folder in your computer and selecting a “Send With Pando” option that appears after the software application is downloaded. Selecting this also opens the familiar sending window. But this works only in Windows.

The 95-megabyte video took eight minutes to upload, and nine minutes to download — impressively fast times. Another Pando Package filled with 44 high-resolution digital photos totaling 65 megabytes took six minutes to upload, and six minutes to receive.

But Pando can’t entirely overcome slow Internet connections, so your speeds may vary considerably. This is especially true on the uploading side, as even broadband cable and DSL connections typically offer upload speeds that are a fraction of their download speeds. In our tests, at our office and homes, our download and upload speeds ranged from 30 kilobits per second to 250, depending on where we were and when we were testing.

Even if you didn’t see any speed improvement with Pando, you’d still benefit from the sheer ability to send huge attachments. That’s a big deal.

On July 25, Pando Networks will introduce a special plug-in for Outlook, making it even easier for users to send huge files without worrying about inbox congestion. And the company also has plans to introduce plug-ins for Web-based email programs like Google’s Gmail and Microsoft’s Hotmail.

If you’re tired of bounced emails, and of using Web sites to share your personal videos or photos, Pando is a straightforward solution that anyone can understand in a matter of minutes. It’s a great solution to a vexing problem.

• Email: MossbergSolution@wsj.com.