ELIM is an elisp instant messenger daemon (using libpurple), with a sexp based control protocol. Developed by fledermaus.
The README included should tell you everything you need to know to get started with basic IM functionality.
The reference IM client implemented on top of ELIM is Garak, it is included with in the ELIM tarball.
libpurple (v2.4.3) supports the following protocols officially:
Others are available as 3rd party plugins: http://developer.pidgin.im/wiki/ThirdPartyPlugins#AdditionalProtocols
Question: Is anyone successfully using this with sipe? I have it working with pidgin but can’t get it to work with elim… http://sipe.sourceforge.net/ --mgalgs