I was looking for this information and with a bit of digging around I turned up this:
https://bitcointalk.org/index.php?topic=10617.msg152161#msg152161There was a thread in bitcoin land with a bounty for an open source Mining pool. Apparently they got it working and even has a web interface. A great place to start for someone wanting to see up a pool. I'd give it a go, but I'm just to busy at the moment to maintain it even if i did get it working. The difficulty is going up so much that without a pool it's going to be pretty hard to mine.
