I know that the book thread is going to take off any minute now. In the mean time, I thought it would be a good idea to share your favorite podcasts.
Here are a few I listen to:
Astronomy Cast: I've already mentioned a while back. This podcast covers a wide range of topics - from planetary science to cosmology. It's a great resource; lots of information, yet easily approachable for novice enthusiasts.
The Skeptics Guide to the Universe: a podcast that revolves around science and critical thinking. Lots of science news items as well as input from the skeptical community.
TechStuff: from the folks at How Stuff Works, a great resource in and of itself. TechStuff covers everything and anything relating to technology and its modern applications - everything from operating systems to electric guitars to fiber optics.
Enjoy!