Digital Podcast is a podcast directory.
It has a single level category listing meaning that if the podcast you want to find isn't on the first page you probably aren't going to have the patience to find it. Most of the categories have 20+ pages of podcasts. So Good luck finding what you want.
To add a podcast you have to be a registered member. They list 15,000 podcasts, 17,000 members, hmm, there doesn't seem to be much that a registered member can do other than add a podcast. There are forums, which have topic areas most suited to podcasters.