BabasChess
A new revolutionary internet chess client for Windows.
http://www.babaschess.net/

Coccinella
A free and open-source cross-platform instant messaging client with a built-in whiteboard.
http://coccinella.im/

Voice Over Protocol Calls
Enjoy free international and internet video calls with Skype. Skype provides internet calls, conferences, sms and international calls online
http://www.skype.com