SIP

Session Initiation Protocol

http://www.cs.columbia.edu/sip/ signaling protocol for Internet conferencing, telephony (VoIP), Presence Detection, events notification and Instant Messaging

http://www.sipforum.org/

http://theappleblog.com/2005/07/01/flexible-communications/

Phone Gaim integrates SIP into GAim (actually I think it's a fork of GAim). http://www.phonegaim.com/

• and an extension for AdiumX? http://www.adiumxtras.com/index.php?a=xtras&xtra_id=2058

also...

SIP is a tool that makes it very easy to create Python bindings for C++ libraries.

http://www.riverbankcomputing.co.uk/sip/index.php

from the PyQt people

also: Statistically Improbable Phrase: 2005-07-16-AmazonCapitalizedPhrases