SOFTWARE CHAT:

Miranda : http://www.miranda-im.org
Msn Messenger : http://messenger.msn.com
Yahoo Messenger : http://messenger.yahoo.com
QIP : http://www.qip.ru
Gaim : http://gaim.sourceforge.net
JAJC : http://jajc.jrudevels.org/

SOFTWARE IRC :

HydraIRC : http://hydrairc.com/
Talkative IRC : http://www.talkative-irc.com/
IceChat : http://icechat.net/

SOFTWARE VOIP :

Skype : http://www.skype.com/
Google Talk : http://www.google.com/talk/
Voip Stunt : http://www.voipstunt.com/en/index.html
Gizmo : http://www.gizmoproject.com/
Gingo : http://www.wengo.com/