Atomic Array is a cast I just picked up because of their hour-long interview with one of the creators of Geist: The Sin-Eaters. The interview was very good, and I look forward to listening to more of their stuff.
I also have enjoyed the Walking Eye podcast for their AP's followed by reviews. They do character creation together, 3 or 4 sessions of AP, then a review show, and it's one of the best, straightforward review shows I've listened to for this reason specifically. After reading the Mouse Guard rulebook, their treatment of the product really shored up any confusion I still had, plus they interview Luke Crane afterwards, which was kind of neat.
'Course RPPR is still tops
Sidenote: this is unfairly snobby of me, but I have a hard time listening to podcasts out of England. I enjoy a good English accent and still love the original Office and Spaced, but something about English accented radio throws me off.