Team Speak is a stand alone program that allows individuals to talk to each other in real time while playing! It's fairly easy to download and set up, but unless you intend to expend a few $$$'s I'd find a club that already has it for you to join to avoid having to reach for the old pocketbook! Note a headset, with microphone is pretty much a necessity to get the most out of TS, but those can be had for very little.
URL: http://teamspeak2.bplaced.net/
Phil aka., Coyote