Harvard philosopher Michael Sandel discusses the moral limits of markets in this, the 100th episode of the Philosophy Bites podcast. Sandel was the BBC 2009 Reith Lecturer. His four Reith Lectures are now available here.
You can also listen to Michael Sandel on Enhancement in Sport (a topic that is relevant to the 3rd of his Reith lectures) on an earlier episode of Ethics Bites which we made for The Open University. Open2.net has a site with some audio and links about the 2009 Reith Lectures here.