"Creating Custom Podcast Feeds Using del.icio.us" is a neat article writing about how some people are using the power of del.icio.us to create podcasts.
The basic idea is to mark mp3's that you are interested in and then since del.icio.us can make rss you can then use the url that this particular tag makes to form a url you can then feed iTunes or some other podcast enabled program.
Very awesome. And apparently, the parent blog entry has that poster doing things like putting in auto-generated audio that can preface the mp3's. Wow!