I only added two podcasts from actual libraries: What's New At The Lunar & Planetary Institute and one from a university library in Massachusetts that does podcasts about film. I also subscribed to a couple of ones that were just my own interest. They were interesting to listen to, though I only had time to listen to a little bit of each.
I can see where podcasting might be a useful tool for information from the library. A lot of radio shows have podcasts and you can hear music and interviews online that way. I think patrons might be interested in listening to audiobook productions or perhaps hear when authors come to the library to lecture via podcast. I have listened to a few podcasts before. My brother is a computer geek and used to listen to some guys talk about Linux and whatnot, so I remember that. It's been awhile, though, and I had never sought them out on my own before. This was interesting. I might listen in again sometime...if I have time.