With the variety of podcasts available on the Web, it would be a good idea if you had a convenient listing of sources of podcasts of different genres. Here are a few sources – you could call each of them a directory of directories.

Directory of Interesting UK Podcasts for News, Radio, Sport, Education – TheBigProject

Educational podcasts for teaching and learning – RECAP Limited

List of directories focused on Audio and Video Podcasts - Podcast411

Accurate and up to date content from only British podcasts – BritCaster

Podcasts and Podcasts Directory – itunestracks