You probably have more success in posting to the JGroups dev and/or users mailing lists (http://sourceforge.net/mail/?group_id=6081).
That said, Manik once started a JVoip project for Voice-over-JGroups, and we even had a decent conversation over JVoipd between Switzerland and London. You can check out JVoip at cvs.forge.jboss.com/cvsroot/jboss, module is "JVoip".
There's also fisheye: http://sourceforge.net/mail/?group_id=6081.
A long time ago (1999) I also had 1 or 2 student projects which prototyped audio/video apps: http://www.cs.cornell.edu/home/bba/ under "student projects".
Hope this helps,
The goal for JVoip (which is, sadly, now dormant due to lack of time) was to have it run on J2ME phones using the JGroups-J2ME port as a transport.