I have been hearing a lot about this topic, and searches in Google turn up a lot of results, but if you are looking for an article to read yourself, check this one out.
http://radio.about.com/od/podcastin1/a/aa041805a.htm
They bring up a lot of good opinions and ideas so if you are a podcaster and have any type of audio in your podcast, you might want to consider reading this one and doing some additional research.