There is new SIP server software available for multi-party IM chat. SIP chatserver is an open source conference bridge that supports MSRP chat sessions. It can be used for ad-hoc conferencing by SIP end-points.The project is hosted at http://chatserver.ag-projects.com
The server implements relevant features from the following standards: - MSRP protocol RFC4975 - MSRP ad-hoc multi-party chat sessions draft-ietf-simple-chat-03 - Common Presence and Instant Messaging (CPIM): Message Format RFC3862 - Framework for Conferencing with the Session Initiation Protocol (SIP) RFC4353 - Framework for Centralized Conferencing draft-ietf-xcon-framework-11 - Conference event package RFC4575
The software is provided under the GPL LICENSE.