This add-on adds support in the Thunderbird Chat feature for the AIM, Bonjour, Gadu-Gadu, GroupWise, ICQ, MSN, MySpaceIM, Netsoul, SIMPLE, Sametime and Yahoo! instant messaging protocols.
This is done by leveraging the work done to integrate libpurple (the library behind Pidgin) into the back-end of Instantbird. All the code for this is freely available at http://lxr.instantbird.org/instantbird/source/purple/
If you prefer a standalone chat client with all these protocols integrated by default, you can try Instantbird (http://www.instantbird.com/