I just came across these excellent tutorials from Buzzsprout:
Audacity Tutorial: 17 Essential Podcast Recording & Editing Tips
Loads of stuff about settings, filters, export quality (although they recommend exporting to 256kbs, four times the quality of the 64kbs that most people recommend for mono audio for a podcast).
Podcasting 101 Guide:How to Make a Podcast
This is a good overview of getting started, including planning, equipment setup and distribution.