Thisnetwork has educational podcasts at all grade levels in all subject levels.
Not sure how this will link; I'm guessing you'll have to use your U of A login to access, but this article looks at how to select quality podcasts, how to organize them and how to integrate them into your class. One of the best features of the article may be the list of links at the end.
This article looks at how to actually create a podcast with students and how to incorporate them into the library. Again, they've given a great list of links at the end of the article.