Hi if you're looking for places as a programmier look at this:
[
^] i used that for my own IM-Chat for Call and video chat.
if you're looking for softwares this isn't really a forum to ask in, but why not use skype, or if you need something controlled then ventrilo or teamspeak? i know all of those does not have video but i'll say hearing eachother is the most importen thing... also there is something called "raidcall" its free but are mainly used by MMO-gamers