I'm not aware of too many podcasters yet in the SQL Server space. However, the thought leader in this space (in my mind) is recently christened SQL Server MVP Chuck Boyce.
Chuck posts updates on all of his webcasts at http://chuckboyce.blogspot.com/. You can also see some of the latest goings on in podcasting at the SSWUG website, owned by Steve Wynkoop.
I'm strongly considering jumping in with some podcasts of my own. But if I do, I'll certainly hand them off to Chuck and Steve. I'd love to hear your feedback about weather podcasts are of interest to you or just a passing fad.