ccMixter-meister Victor Stone points to the definitive list for the moment of podcasting safe music resources at Dave’s Imaginary Sound Space. Many CC-licensed music sites are listed, including many I hadn’t seen before.
Dave’s list is a great place to start if you’re looking for CC-licensed music for your podcast or otherwise. We have an audio page too.
Victor has another valuable recent post on What Licenses Make Sense (To Me). You have to make your own choice when licensing content, but it’s always interesting to see inside someone else’s thought process on the matter, particularly someone with the perspective of Victor.