lol
rather than me explain it you can just read for yourself..
quick synopsis
Skype is the next phenomenon from the people who brought you KaZaA. Just like KaZaA, Skype uses P2P (peer-to-peer) technology to connect you to other users – not to share files this time, but to talk and chat with your friends.
The technology is extremely advanced – but super simple to use... You’ll be making free phone calls to your friends in no time!
check it out here!