If you don't already use Skype, you really don't know what you're missing. Skype is the predominant desktop VoIP application: a softphone and a peer-to-peer (P2P) network that operate over the Internet to link people of all stripes around the globe. In fact, Skype has become a verb as well as a noun. You can use Skype to call people, or you can Skype people—hence this chapter's title. Oh—and you don't have to worry about finding somebody to call (that's been my problem with iChat AV), since Skype has been downloaded 150 million times and averages anywhere from 1 million to 2 million people logged in at a time.
Skype lets you make free, Internet Protocol (IP)-based phone-style calls to any other Skype user and allows you, through optional paid services called SkypeOut and SkypeIn, to place and receive calls to and from regular phones via the Public Switched Telephone Network (PSTN). Skype's sound quality is often reported to be superior to that of a traditional telephone, to boot.
Skype has several things going for it that other VoIP softphone solutions don't. It's the only P2P softphone application that runs on Windows, Mac, Pocket PC, and several flavors of Linux (Fedora, SuSE, Debian, and Mandrake, anyway). It's also the only softphone application that implements its own network and signaling protocol.
There's a reason for this proprietary characteristic of Skype's design despite all the great open VoIP standards such as Session ...