We offer an open library to support serverless VOIP phonecalls for Instant Messengers.
Currently we work to implement Tstone into our partnerprojects, which are Retroshare.sf.net Serverless Instant Messenger and (serverbased) Multimessener SIM-IM.org
At the moment tstone supports windows, but the system basic lib is on ptlib so we can deploy it to linux after we have changed the code. We compile it on VC++ 6 sp5, if we can compile it, you can see some faq about how to compile h.323 env setting. As well we made a stable kadC dht core.
1.0 or 1.1 will be a stable version with windows installer and possibly a QT4 gui, and we prepare a joint venture with our partnerprojects to implement tstone VOIP phonecalls into their messengers.