If you're the type of person who gets data withdrawal every time you're removed from your Internet connection -- and it seems like there are more people like this every day -- you'll definitely appreciate the ability to get Internet service via cell connection. I'm not talking about the little screen on your cell phone; for many applications, that's too small to be valuable. I mean using a cellular modem to connect your laptop to the Net via cell phone service.

Devices that plug into your laptop computer's USB port, available from most of the major cellular providers, allow you to roam the universe while staying connected to your e-mail, Instant Messenger buddies and Facebook.

I have recently been field testing the Sierra Wireless USBConnect 881 cellular modem from AT&T. Like other cell modems, the USBConnect 881 attaches to the USB port in your computer to give you wireless access to the Internet. That means you'll be able to roam to your heart's content and have an Internet connection almost anywhere you go -- as long as you stay within the reach of AT&T's cell network.

The USBConnect 881 is a bit different than other cellular modems I have tested, though.

The biggest difference is that it is plug-and-play with Microsoft Windows. Simply plug it into your USB port and wait a few seconds. The USBConnect 881 automatically installs itself. That might not seem different to you at first -- until you realize that the modem doesn't come with an installation disk like other cellular modems. The software you need is stored right on the device in onboard flash memory. So unlike other cellular modems, you never have to insert an installation CD. With more portable computing devices than ever being released without internal CD drives, this could be more than a nice touch; it could be a necessity.

Even if you have a CD drive on your laptop, the internal installation software can still be handy -- because it allows you to move the modem quickly from computer to computer without having to have a CD with you at all times. Recently I was with an associate who expected to find Wi-Fi at our destination, but was disappointed when the Wi-Fi hot spot wasn't there. I was able to hand him the USBConnect 881, and in a few minutes he was surfing the Web at 3G speeds.

Another distinct feature of USBConnect 881 is its SIM card. This is a small plug-in card that holds your phone number and other vital information about your cellular account. It's used by AT&T in all its phones, but not in Sprint or Verizon phones. The SIM card lets the USBConnect 881 know which cell phone data account through which it is supposed to connect. So if you have two cellular modems or two cell phone accounts, you can mix and match them with the appropriate cell account -- a feature that is particularly handy if you have accounts with limited data privileges before you get charged. For unlimited data accounts, this is less important, although still handy.

The USBConnect 881 runs on the AT&T 3G network and can accommodate an external antenna to make it faster and less power consuming in areas where the cell service is weak. That won't be a problem in most major cities and on frequently traveled highways, but could be an issue in valleys that are hard to reach by cell signals, or in places outside the AT&T coverage zones.

Like with other cellular modems on various carriers, you can get a highly discounted price on your USBConnect 881 by buying it with a cellular service contract.