I've used Podcasts with my iPod. Not anything library-related though, just the Couch to 5k running plan.
For this exercise I added the Open Stacks podcast to my Google Reader account... which I haven't used since Week 4. Easy enough to do, but I didn't really find any library podcasts of interest to me. There are quite a few of them, but the ones I saw mainly related to the goings-on at a specific library, e.g. Arizona State University, or were about US library news, so they may be of passing interest to an outsider but not really worth subscribing to.
Also Yahoo podcasts says this: "Yahoo! apologizes deeply, but we will be closing down the Podcasts site on Oct. 31, 2007."