I first heard about Internet telephony back in 1985, when MIT professor Steven Burns told me about an "Etherphone" that some researchers at Xerox had created to send voice over a computer network. The system worked by taking a person's voice, digitizing it, breaking that digital data into packets, and finally sending those packets over a high-speed network. At the other end, another Etherphone reversed the whole process. Neat technology, I thought, but far too computationally intensive and wasteful of resources to ever be practical.

How wrong I was. In the past 18 years, computers have gotten more than 1,000 times faster and networks nearly 100 times faster, but the human voice has remained basically unchanged. As a result, it's now dirt cheap to send reasonably high-quality voice over the Internet. And with programs like Microsoft NetMeeting, Apple's iChat, and Skype, it's relatively easy for anyone with a decent PC and sound card to set up a two-way voice or video conversation over the Net-provided that you don't mind making all of your phone calls in front of your computer, and that the only people you want to call are other people sitting in front of their computers.