Much of the music used on Circle of Willis comes from a single source--the music of classic Tucson alternative rock/pop band, THE NEW DRAKES (formerly just "The Drakes"), whose core writing team is Tom Stauffer and Gene Ruley. I've been a fan of these guys since I moved to Tucson for graduate school in 1996, and it was thrilling to me when they gave me permission to use their music for the podcast.
For a little background on this band, whose "collective talent and creativity … always far exceeded its financial success," check out this 2007 piece from the Tucson Weekly. More importantly, you can still pick up their music here at Amazon.com. If you find that they're all sold out, write to me and I'll let them know!