Ryan Friedman of Auction Report Blog radio does a weekly podcast where he talks about the sports card (& memorabilia) hobby & interviews the owners of auction houses. He does them very inconsistently, like one each week over a span of 2 or 3 months, then not another one for 3 months. Many of them are really good, though.
http://www.blogtalkradio.com/auctionreport
Also, I understand Andy Madec does a radio show in California, which can be heard/downloaded, but I haven't heard it.
I would think that a vintage card podcast would be really good, interviewing different collectors with their different expertise (Old judge, zeenut, T206, etc,...). I think I suggested it a few years ago, but nothing came of it.
Alan