Podastpickle.com http://www.podcastpickle.com/cast/1273 and Podnova was where I look ted to find some pod casts that related to libraries.
For both sites, I came across pod casts on book reviews, and occasionally some audio books where I was able to listen to a particular book, for free.
At first it was a bit difficult to look for a podcast that I liked although I used tags as a shortcut, as lots of them did not seem very relevant to what I was looking for.
However, after searching through a couple of pages I could find a couple that I liked- which I also added to my Bloglines account.
I tried Podcastalley.com as well, but I think it asked me to join up and also to pay.
Podastpickle.com and Podnova does not require you to join up or anything. Very simple.
I think the two sites that I have mentioned above, are quite useful as I can listen to the reviews of a book before reading the book. As for audio books, they are very good as it means that I can always listen to the story as I do some other work. (Allows me to multi task)