Millions of people, have embraced the flexibility of a networking system that involves no wires at alla cordless networking technology called WiFi or 802.11 ("eight-oh-two dot eleven"). (Your Macintosh friends probably call the same thing AirPort, because that's what Apple calls it.)

To get onto a wireless network, your PC needs a WiFi transmitter. Almost every laptop sold today has WiFi built in. You can also add it to a desktop in the form of a wireless card or USB adapter; either way, you gain a little antenna. Once all of your equipment is wireless, that's it: your PCs can now communicate with one another.

The real point of all this, of course, is to get onto the Internet wirelessly, so you can join the ranks of people who casually move around from the TV couch to the desk with their WiFi laptops, in wireless touch with their cable modem or DSL connection the whole time.

In that case, you also need an access point (about $50)a box that connects to your router or hub and broadcasts the Internet signal to the whole house or office. The usual suspectsLinkSys, Netgear, D-Link, and otherssell these access points (also called base stations).

Now, 802.11 equipment has a range of about 150 feet, even through walls. In concept, this setup works much like a cordless phone, where the base station is plugged into the wall phone jack and a wireless handset can talk to it from anywhere in the house.

Wireless networking is not without its downsides, however. You may get intermittent service interruptions from 2.4-gigahertz cordless phones and other machinery, or even the weather. Furthermore, big metal things, or walls containing big metal things (like pipes) can interfere with communication among the PCs, much to the disappointment of people who work in subways and meat lockers.

Wireless networking isn't as secure as a cabled network, either. If you drive around a typical middle-class American neighborhood these days with your wireless-equipped laptop turned on, you'll be surprised at how many home wireless networks you can get onto, piggybacking onto other people's cable modems because they failed to turn on the optional password feature of their wireless systems.

Wireless gear comes in several flavors, each offering different degrees of speed, distance, and compatibility. They have such appetizing-sounding names as 802.11b, 802.11a, 802.11g, and 802.11n.

So what's the difference? Equipment bearing the "b" label transfers data through the air at up to 11 megabits per second; the "g" system is almost five times as fast. (Traditionally, geeks measure network speeds in megabits, not megabytes. Here's a translation: The older "b" gear has a top speed of 1.4 megabytes per second, versus more than 6 megabytes per second for the "a" and "g" stuff. Remember, though, you'll usually get around half that speed. Your wireless network uses a lot of the bandwidth for such network housekeeping chores as correcting transmission errors.)

The beauty of 802.11g gear, though, is that it's backward-compatible with the older "b" gear. If your laptop has an 802.11b card, you can hop onto an 802.11g base station simultaneously with people using "g" cards. And if you have an 802.11g card, you can hop onto older base stations. You won't get better speed, of course, but at least you won't need a separate base station.

(That's not true of "a" equipment, though. 802.11a cards require 802.11a base stations, and vice versa, and have much shorter range. Word to the wise: Don't buy "a" gear. In fact, you should go for "g" whenever possible. However, don't be scared off by 802.11a/b/g gear, since it can talk to all three types of networks.)

There's even such a thing as 802.11n, an emerging standard due to be finalized in 2007, that offers better speed and better range (thanks to multiple antennas) than its predecessors. Remember, though, that you won't get the better speed unless both your base station and your networking cards speak "n."

Don't buy faster equipment thinking that you're going to speed up your email and Web activity, though. A cable modem or DSL box delivers Internet information at a fraction of the speed of your home or office network. The bottleneck is the Internet connection, not your network.

Instead, the speed boost you get with "g" gear is useful only for transferring files among computers on your own network, streaming video or audio to (and from) your home theater, and playing networked games.

Finally, the great thing about wireless networking is that it all works together, no matter what kind of computer you have. There's no such thing as an "Apple" wireless network or a "Windows" wireless network. All computers work with any kind of access point.

Still, nothing beats the freedom of wireless networking, particularly if you're a laptop lover; you can set up shop almost anywhere in the house or in the yard, slumped into any kind of rubbery posture. No matter where you go within your home, you're online at full speed, without hooking up a single wire.