The only podcasts I ever listen to with any frequency are from npr, so I had a feeling I knew that there were a lot of people out there making podcasts, but was still surprised by the sheer amount of them. More than anyone could ever listen to. So, how does one find the best? I'm not really sure. Podcastalley and podcast.net did break things down by genre, but there are still so many shows available to listen to that I'm not sure how I would recommend a person start without suggesting that he just try some. I suppose that blogs and podcasts would work together well, if the person doing them was willing to provide both. I'm sure that nany people also recommend podcasts to others the same way one would recommend a book, so I guess that I would tell someone to keep an eye for podcast recommendations from people you like (or despise) to read.
I found lots of manga and comic book review podcasts mixed in with other book review podcasts that did not explicitly state what they were in the title. Part of the difficulty of the directory, is that it does not list with the author is next to the show. If there is author information listed, you need to expand the menu to see it. Sometimes it is not listed at all. So, until further verified, author credibility must always be suspect.