I think this podcast is pretty well known here, but in case anyone's new and hasn't heard of it:
Health Podcast | UW Radio | Health Expert Interviews | Underground Wellness
It's also available in iTunes.
IMO, this is the best health-oriented podcast by a pretty fair margin -- the sheer variety and quality of the guest list, and the presenter is top-notch.
A word of warning, though. If you're listening on a iPod, turn the volume right down till the intro's over, because he always starts by coming on and shouting: "YO! WHAT'S UP! fit to wake the dead.
I stumbled across it a couple of weeks ago - I absolutely love it and have learnt so much from it. (I have ended up with a looooong reading list as a result though!)
Yeah, that must be the only drawback.
There are some amazing episodes that have totally changed my view of things -- like the one where a professor explains out of his inside knowledge exactly how the pharmaceutical industry works. I can't remember his name -- an Irishman teaching medicine at a university in Wales.