I'm open to volunteers to judge the entries (I will probably be one, so looking for about 2 others). That could be programmers who aren't taking part who want to give their opinions, or even people from the Writing/Design area of the forum. I think for each entry the judges should assign scores, and also write a little review pointing out what they liked, what they didn't and what could be improved.
As for XNA, I have it on my PC, and anyone with a windows system should be able to install the XNA framework to run the games. I do not have the XNA Creators Club though, so cannot test anything on an actual Xbox 360 (I do have a 360 controller that I can use for Windows XNA games, but I wouldn't rely on all judges having that).