well, i really only play WoW online on the comp these days, and most of the guilds that use VOIP use either Ventrilo:
either works fine, but are a bit different. go to sites and see which you prefer, or to game and ask those you play with.
hope this helps
does anyone know of a software program that will allow voip for multi-gaming only. I have tried Roger Wilco and was wondering if there is anything out there that is better.