Hi RussellH, I did not see your original post as I was away at Lostock (as were a lot of others!). I have been listening to astro podcasts for a while - I found the best one is Slacker Astronomy with Universe Today a close second. I also enjoy listening to the ABC Radio National Science Show - it is always interesting though only now and again are there astronomy stories.
When I started out I listened to a few podcasts - one of the first ones was a Northern Hemisphere based observing program (you know, what is up at the moment) - I don't remember which one it was but the production quality was very bad and the presenter was, well, there's no kind way to say this, really boring.
I'd say go for it, try it out - but keep the production values high, make it interesting and people will listen. As far as making an astronomy podcast "for the masses" I'm not sure how successful you will be. I think an audio talk on astronomy will only ever appeal to an audience who is already interested in astronomy - to interest the "masses" you really need to appeal to the visual sense.
Just my opinion - Good Luck.
