And if you haven't experimented with them yet, podcasts are just mp3 files. You don't need an iPod ( or iTunes software ) to play them. You can download the files and listen to them later ... you could even burn them to listen on the ride home from work if you wanted.

Science Friday: Making Science Radioactive

Although they don't cover things in as much depth as I'd like, they pick some fascinating topics, and do give you a lot more understanding than the news.