Yes, ventrilo VOIP servers are heavily used by the gaming world. Essentially you have a server with a bunch of channels that you set up, to allow users to go into channels and speak to each other. Channels can have as many users as you like in them, and you can have as many channels as you want. The limit is defined by the total number of slots you have on your server. My vent server is 68 slots, so I can have 68 people in one channel or scattered throughout a bunch of channels when people want to be in smaller groups or alone or whatever... It is very handy, not just friends and gamers get together on it, but family members from around the world get together on it too instead of spending on long distance calling.
It is like the ajax chat on here, except it is totally live, full duplex, and is voice instead of type...
