Podcasts have become the current rage that is sweeping the net.Like all that get pulled in by this powerful/useful phenomenon the academia has also succumbed to it.Over from Productive Strategies there is nice post listing several of the academic podcasts that are available for free.If you can then please do go over to the comments section also,they contain some useful links to study materials and several more.It is unfortunate that i missed this post this long.But as they say better late than never ;-).