I'll give Credit to TechLEARNing.com, which you should visit, before linking directly to the site below. This is a good high level overview for educators to understand what "podcasting" means, how the process works, and what value it offers to education.
Source: Podcasting 101 for K-12 Librarians
In my own blogging, I've often considered podcasting, netcasting, vidcasting, webcasting, etc. Essentially all the same, just many different ways to say posting an audio or audio/video recording via RSS feed. I'm particularly thinking about whether I should start looking for LiveMeeting presentations that our field in the Education vertical are recording and possibly posting them in Soapbox for public archival and feed-based aggregation.
What topics would be most valuable to EDU?