WHY does Skype get so much hype? Sure, this software lets you make free "phone calls," computer to computer, anywhere in the world. But it wasn't the first such program, it's not the most feature-laden, and it's still a mystery to most people over 25.

Yet somehow, Skype is changing everything. Twenty-five million people are using it to make free calls, much to the annoyance of the phone companies. College students call home and friends with it. Business travelers keep in touch with the family. Visitors to the United States chit-chat with their buddies in Europe, Japan or wherever. The software -- free from skype.com and available for Mac, Windows, Linux and PocketPC -- is pitifully easy to use, and the sound quality is more like FM radio than a phone call.

Skype's popularity has caused some impressive ripples in the fabric of business and society. The word is now a verb, à la Google ("Have your people Skype my people"). Last fall, eBay bought Skype for $1.3 billion and 32.4 million shares of eBay stock. And most intriguing of all, an entire industry of Skype accessories has sprung up.

But one niggling footnote continues to dog Skype: to make free calls, you and your conversation partner must sit in front of your computers, nerdlike, wearing headsets. You can call regular telephones, but that's not free. (Rates are complicated, but 2.1 cents a minute is typical.) And you have to sit handcuffed to your computer.