I'm such an idiot!
We have a Ventrilo server on mtbs3D.com which lets users voice chat with each other. Unfortunately, while I listed BF2 as a Ventrilo voice chat game, I didn't realize I had to list every individual game you can voice chat with. This is something that isn't in the users' control - my bad!
I went through my gaming library for all the multiplayer games I have, and added them to the list.
You can even voice chat in Klingon Academy if you wanted to!
Incidentally, every game I listed has been - or will be - tested for certification. We haven't scratched the surface!
Please let me know if you have games you would like added to the list. They do not have to be S-3D compatible or certified to be playable in Ventrilo.