Raidcall is a free,low-latency voice solution for professional gamers.
Raidcall is designed for group communication while gaming, especially for games requiring tight teamwork such as FPS and MMORPG games. It can provide clear voice quality with extremely low latency, and there is no need to rent servers or set up a server by yourself. Raidcall makes group communication easier.
System requirements: Windows 7, Vista, XP or 2000
They updated it so you don't just have to label your game list to select a "popular" game. You can just select "Others" on the bottom and make Minecraft related voice chats for multiplayer. It's free and should be a good quality... Suppose to have a ingame interface, but not sure if it really works.
If you do get involved with such technology, for the good of gamers worldwide, do suggest more games and ideas to them... As they seems to see things on a "technical" side rather than doing research on games themselves... But they do listen to people.
Now what we need next is a adhoc party for the PC... PC to PSP via USB cord can do. If the PS3 can release a adhoc party software, it's possible for software developers to replicate it to work on a pc, since:
1) Instant access to the internet.
2) Easier to chat and use side programs to communicate (your sitting in front of a monitor/laptop, not a TV for a ps3).