well jus' sayin =p. I thought I might put it out there, not necessarily for Team 9000...for example: You might have another game you use which you might want to have a private VoIP xD.
imVox is a free VOIP which works in ways similar to Mumble, Ventrilo and Teamspeak.
It is free, and relatively simple to use.
The downside? The Servers you can make only hold up to 30 people at once.
:D