SIP is another popular protocol used for VoIP, and it also has an IM (Instant Messenger) analog in the form of SIP/SIMPLE. SIP/SIMPLE is an open protocol with a documented specification. . The Live Communication Server (LCS) has support very similar the Sip/Simple protocol, but the SIP implementation by MSN has non standard especifications. This pidgin plug-in gives that support and it was called SIPE (SIP Exchange). . Homepage http://sipe.sourceforge.net