Facebook Chat moves to XMPP/Jabber standard
Facebook has followed through on its plan to add support for the open standard XMPP/Jabber instant messaging protocol to Facebook chat. Plans were originally announced in 2008 but little was heard in terms of development. In the meantime, various open source IM application developers created plug-ins and extensions to support Facebook's own protocol.
Now those plug-ins are no longer needed; if your instant messaging application supports XMPP/Jabber, then it is possible to connect to Facebook Chat. Pidgin, Adium and Miranda are among the open source clients which offer this support as standard. Instructions on how to connect to Facebook Chat for these and other IM clients are available on Facebook's site tour pages.