Actually, it's not "news you put on your ipod." It's an encapsulated web broadcast. Can be music, news, entertainment, sports, anything. But they're typically done by amateurs who would have no hope of ever being on TV or radio who just talk about subjects near and dear to them because they love it. However, pros have started to join the fray and now we have a glut of people who are heard very commercially also doing podcasting. Podcasts are posted for free download on the web. You can typically use RSS feed aggregators to find them and autodownload them to your computer or MP3 player. It can play through an audio player whatsoever as they are usually just MP3 files.

I listen to Bears Blitz (Chicago Bears), NFL Rants and Raves, Ebert and Roeper, The MIX Morning Show, Skinny on Sports, Diggnation, Cush: Things I Say, iTunes New Music Tuesday, MrJerz Does the Podcast Thing (friend of mine), NPR Sunday Puzzle, Podfinder, PodQuiz, The Mac Observer Mac Geek Gab, and Winecast. All are available through iTunes and elsewhere (except iTunes NMT and Podfinder which I think are exclusive to iTunes).

If you want to see what's available, you can use sites like Odeo.com and Podcast Pickle, should you not want to use iTunes.