I currently have a voip linux product called Mangler. See their homepage here: http://www.mangler.org/
This is a client for the popular windows only software called Ventrillo. It allows several people to talk together, share information, discuss different topics. They recently released a beta version of their newest product and I use it at work for conferencing under Pardus 2008.2. I had to compile it manually, but a pisi package would be great.