I use to be a big time online gamer, and we would sometimes use these VOIP systems as voice communication applications, while playing. Eliminating the keyboard only communication, this freed up the constant use of the keyboard as a communications device, and a controller. I'm not 100% sure if these applications still work 100%, but hey, most, if not all of them are free and could be a good avenue towards getting everyone to join in RT chats, due to not liking the odd and wanky ones being used as of now. Give it/them a try and see what you think.

http://en.wikipedia.org/wiki/Roger_Wilco_%28software%29

http://en.wikipedia.org/wiki/Mohawk_Voice

http://en.wikipedia.org/wiki/Mumble_%28software%29

http://en.wikipedia.org/wiki/TeamSpeak

http://en.wikipedia.org/wiki/Xfire