From the makers of How Stuff Works.com. The website has a lot of articles and links to outside sources, too.
What's great about it?
They explore everything! The hosts are total geeks, so they usually start their shows with somethig super nerdy, and then link it to science, technology, or sociology. It's way cool!
P.S. When I say they are total geeks, I really mean it. The first episode I listened to was about the science of Frank Herbert's Dune. D&D makes a frequent appearance. If you want to learn interesting things, this is the podcast for you.