The Podlounge is an Australia based podcast directory. But being based in Australia doesn't seem to limit their content to Australia.
They have a decent set of topic categories, but it appears that even so the topic category listings still have lots and lots of listings. I think when a category listing is split over lots of pages, the user is not going to wade through the whole list. It's better to have really focused topic categories.
Anybody can add a podcast to the directory.