Well known problem of podcasting is...
that sound can't be indexed into text and searching is impossible without a transcript or something. So you have to carefully choose the keywords around to link to the podcast audio file.
Now since podcasting is somewhat not just a techy thing but a social thing, people will blog or link to the podcast with their own descriptions and explanations. So maybe that could ease the pain on search...but still it's a problem FWIW. No?
