VGA Planets 4 is out in open beta. I suspect it will stay that way, never quite be released. They keep adding to it. Its already to the point that the game options would fill a fat book. I pre-purchased VGAP4 in 2001 and still havent received a real copy of it.
There is a newsgroup for it where the ongoing development and setting up games happens.
As for Dom3 server sites, there 6 servers listed in the server thread that is stickied at the top of the MP subforum.
Then there are the games played the the Strategy newsgroup.
And the IRC Channel.
Then there is the After3 (something like that) site that is a developers hangout and there are games being played there.
There was supposed to be some live-voice channels setup for games but I dont think there was ever an agreement on what program to use.
I suspect that the FaceBook group for Dom3 will start setting up games. I wouldnt be surprised to see groups form on MyPlace, Squidoo, MeetUp, and even HotorNot.
(tracking such things is part of what I do)
Gandalf Parker