Hi,
I had to post a new message here as there is currently an interesting article in the New York Times which looks at this issue, with some quite surprising opinions and numbers...
Publishing - Podcasts - New York Times
Definitely worth a read. I'm still not sure about the relative merits of podcasting a novel vs. waiting years to get an agent or publisher, but at least you have something out there I suppose. I just worry whether this "cheapens" your ideas.