I have not been living under a technological rock lately, so I was aware of the existance of podcasts, I had just never listened to any personally. But basically its like listening to radio programs on your iPod. Various people put together things to listen to, whether its music, talk, whatever. And then you can subscribe to these podcasts and download them. And generally, they're free. There's even a lot of NPR shows on podcast so that you can listen to your favorite shows wherever you are.
Someone emailed me about a podcast (Cycling Insight) where two Australian guys talk about the Tour de France. Which I did not watch nor have any interest in other than Lance Armstrong in tight pants. However, these two guys are pee-your-pants funny. so I've been listening to this one.
If you have the most recent version of iTunes, you can search for podcasts and subscribe to them, then listen to them at your leisure. Another thing about iPods that is totally awesome. Also, another reason why I am wishing I had a regular sized iPod in addition to the mini.