I just finished my first podcast. It is here.
The main technical challenge in a podcast is getting good sound in the original interview. Once you have good sound, you can do whatever you want... edit it, add music, add an introduction...
But if you don't have good sound, you are lost. No amount of tweaking, filtering, or noise removal will help... much. You simply can't fix things like reverberation, white noise, and distortion caused by low quality microphones... no matter how much you try.
When I did the interview for the podcast, I just followed the instructions outlined in Digital Video Secrets for capturing good sound. And, know what?
It worked great. We got excellent quality sound.
(What a relief! Sound has always been--and continues to be--a huge challenge for me.)