From the Wall Street Journal’s coverage of Apple’s podcasting support:
Of course, some podcasters go ahead and play unauthorized music anyway on their shows. Music companies haven’t yet started widely cracking down on the practice. Mr. Jobs says Apple has an agreement from music companies that allows podcasters to play 30-second song clips in their shows.
If that’s true, it’ll make my job a lot easier. I experimented a bit earlier this year with adding short music clips at the beginning of my podcasts. I was hoping for some sort of “Fair Use” coverage. But if this is true, then I’ll be more confident in doing it, working up some real bumper music, intro music, etc.