EconTalk 5/17/2010 Russ Roberts, Professor of Economics at George Mason University and host of the podcast EconTalk, does a wonderful job of presenting an overview of a paper he has written on the topic. It is a open and fair explanation of the events and circumstances that may have resulted in the crisis. Roberts focuses attention on various incentives that may have been in play.
EconTalk 9/29/08 interview with Arnold Kling - Kling was formerly employed at Freddie Mac and starts by explaining how a mortgage works all the way through the real estate bubble and its consequences. Listen to this first as a good basis.
This American Life: "Giant Pool of Money" and "Inside Job" - you may have to pay .99 to get these. They are well worth it.
Also: listen to NPR's Planet Money podcasts.
I make EconTalk and Planet Money podcasts mandatory listening every week. They are always enlightening.
