I recently discovered The Duct Tape Marketing podcast with John Jantsch. This is a great podcast and I have already listened to a lot of the shows he has there.
Like every really good podcast every one of the shows is short, and contains practical and useful information. Also, strangely, John doesn't actually do a lot of advice bits - instead he interviews some truly great business minds including David Allen, author of Getting Things Done, and Daniel Pink, the exceptionally creative author of Free Agent Nation.
If you are looking for additional avenues to leverage your time when you are driving, flying, waiting for a plane / train / bus or just trying to divert your attention at the gym, then this is a very good one.