ICQ

Adium is a free and open source instant messaging application for Mac OS X, written using Mac OS Xs Cocoa API, released under the GNU GPL and developed by the …

Empathy is a messaging program which supports text, voice, and video chat and file transfers over many different protocols. You can tell it about your accounts on all those services …

Imo instant messenger is a web-based service with video and voice chat functionality. imo's web messenger and mobile messenger apps let you IM your friends with AIM, Facebook, Google Talk, …

Kopete is an instant messenger supporting AIM, ICQ, MSN, Yahoo, Jabber, IRC, Gadu-Gadu, Novell GroupWise Messenger, and more. It is designed to be a flexible and extensible multi-protocol system suitable …

eBuddy is a web and mobile messenger which supports various instant messaging services. Features include chat on Windows Live Messenger (also known as MSN), Yahoo! Messenger, AOL Instant Messenger, ICQ,...

qutIM - free open-source multiprotocol ( ICQ, Jabber/ GTalk/Ya.Online/LiveJournal.com, Mail.Ru, IRC ) instant messenger for Windows, Linux, MacOS X, OS/2, Symbian, Maemo/MeeGo, Solaris and *BSD.

Galaxium is an instant messenger application designed for the GNOME desktop. It will allow you to connect to MSN, Jabber, and IRC. You can communicate with your family, friends and …

Zoho Chat is a web based chat system. You can access it using just a web browser and an internet connection. It does not need any software to be downloaded …

Sim-IM is a multiple protocol instant messenger for MS Windows, GNU/Linux, FreeBSD. Sim-IM supports Jabber/XMPP, Google Talk, ICQ and AIM (Oscar), Yahoo! Messenger and Microsoft Messenger (MSN) protocols....

Check ReChat (Android messenger): http://refineandroid.doodlekit.com/ - Facebook, Yahoo!®, Google Talk, WLM/MSN, Jabber/XMPP; - group chat (Yahoo!®, Google Talk, WLM/MSN, XMPP); - free voice calls...