How to add Twitter and Facebook IM support to Pidgin for Windows - Download Squad
http://www.downloadsquad.com/2009/01/18/how-to-add-twitter-and-facebook-support-to-pidgin-for-windows/

Pidgin is a great multi-protocol IM client. Out of the box it provides support for 15 different protocols, including most of the important ones: MSN, Yahoo, Gtalk, ICQ, and XMPP to name a few. Two glaring omissions include Facebook IM and Twitter - both of which are built-in to Digsby by default.