You mean the one they mention on that audio game site, can't remember which one...

It's because the players are probably in the US. If you want to set up your own game using a certain piece of software there's nothing stopping you. Anything that offers voice chat or conferencing will work that's accessible : ventrillo if you can set a server up, team talk alledgedly, and anything else you can come up with possibly including skype if it has conferencing capability.

Edit:
by the way, you might want to check your spelling. Just trying to point it out in a friendly way so noone complains later in a more hostile manner, that and the fact that it doesn't read right in Jaws