While online video will continue to get more affordable and more people will develop the skills required to quickly get quality productions online, there will always be a need for well produced podcasts.
One essential element of a good podcast is a blog post for the show notes. These can include biographical information about the speakers, credit for music or production services and links to additional information. One thing they should include is a minute-by-minute description of the information delivered in the podcast. To see what I mean, check out the show notes for a recent podcast from the folks at Anecdote.
People are pressed for time. They want to go right to the information they are seeking. If they find sufficient value there, they'll often listen to the rest of the production. If you don't make it easy for them to find what they are seeking, they may not listen to any of it.