I also would like to have a way to disable podcast auto downloading on 3G.
I have Cellular Downloading turned off in the Store. However I set my weekly 2-hour music podcast (about 105 MB files) to auto-download, and suddenly my cell data usage says I have received nearly 100MB, and it's only been 10 days since my billing cycle started. I rarely download 100MB of data in the entire month.
Looks to me like the podcast either started or finished downloading on wi-fi, but the bulk majority of it downloaded thru 3G when the device was asleep. I really can't believe there's no setting specifically to restrict podcast auto downloading to wi-fi only. And I wouldn't think it would have started downloading on wi-fi, because doesn't wi-fi stay active during an active download after pressing the sleep button on the phone?
I'm pretty sure the setting in the Store menu only applies to automatic downloading of purchases on other devices, as that's the heading of the screen where the Cell Downloading setting is located.
Really ***** as I was really looking forward to having automatic downloading so I don't have to always check for the new episode release. If not automatic downloading, some kind of notificatoin would be nice.