Hey all. I stumbled upon the Non-Prophets a month ago and enjoy the podcast very much. It is very well done, and I've almost caught up for this year. The same time of discovering it, I also found another podcast called the Skeptic's Guide to the Universe. It is done by the New England Skeptic Society and has been running for a few years now. They have great discussions about skeptical news items of all categories. It isn't a religion focused podcast, but they do go into religious topics such as creationism. I definitely recommend it as a supplement to the Non-Prophets during the 2 weeks in between episodes.
Glad you enjoy the show.
I have to admit that I'm not at all up on podcasts and haven't yet listened to SGU, but we're aware of it, and it's been mentioned on the show a few times.
These boards are rarely used, but if you want to have some discussions with like-minded and like-tasted individuals, the forums at Iron Chariots are pretty active, and it has a Non-Prophets/Atheist Experience board.