Free Messengers

http://gaim.sourceforge.net (A multi User IM)*
http://www.aim.com/ (AIM Messenger)
http://www.google.com/talk/ (Google Messenger)*
http://messenger.rediff.com (rediff IM)
http://ideas.live.com(MSN/Windows)
http://messenger.yahoo.com/ (yahoo IM)*
http://www.ceruleanstudios.com/(Trillian)
http://www.aol.in/(AOL Messenger)
http://www.icq.com/