The term podsafe refers to creative works, often music, who’s licensing allows them to be used in podcasting.
Related definitions: Creative Commons
promonet.iodalliance.com – More podsafe music from the Ioda Music Network – not quite so mainstream but some real gems to found here.
jamendo.com – Some weird and whacky podsafe music can be found here…
musicsubmit.com – A smaller list with the occasional gem.