I'd never really used podcasts before. I added one to my bloglines about Lost, my favorite TV show. I found that a lot of the directories had broken links, or else succeeded in confusing me to death. It took my several tries to find a podcast I could actually figure out how to add to my account. I think I've got the hang of it, now. :)
Podcasts could definitely be used for by libraries. Adding book reviews, etc. to a library website could be a very useful tool for patrons.