Instantbird is a multi-protocol instant messaging (IM) client lets you connect simultaneously to multiple IM networks including AIM, MSN, Yahoo! Messenger, Google Talk, XMPP-based services, ICQ, IRC, and several of the less commonly supported platforms, like Novell GroupWise and MySpaceIM.
Another important aspect of Instantbird is that it is free and open source software, so anyone is free to distribute and modify it, something that will appeal to many developers. Instantbird merges two popular open source projects; it uses Pidgin’s libpurple to connect to the different networks. This library, which is used for developing IM programs, is also used by Pidgin, Adium, Meebo, and several other popular IM programs.
Cross-Platform, Multi-Net Instantbird Brings XUL to IM
By Vangie Beal, March 24, 2009