Think of a podcast as a radio/TV show, except you can enjoy podcasts whenever and wherever you want. Podcasts are about comedy, music, sports, books, politics, walking tours, whatever. You name the topic and you will find a podcast. You can enjoy these shows one at a time. You can subscribe to every episode using ahkpod, itunes, or other subscribing services. When you subscribe, all the newest episodes will automatically download to your iPod, or mp3 player as they come out. Podcasting allows anyone and everyone to produce their own programming for the entire world to see.

With radio you have dozens of stations.  With the Internet you have tens of thousands of stations and podcast choices.  Soon to be million, undoubtedly. Radio stations spend hundreds of millions on a station, so program to lowest common denominator (dummies), since risk is too great.  The end result is alot of station flipping time and seldom best quality choices.  Flipping takes time and is dangerous at times.   Podcasting is a drag and drop every week or month.

Now, I mention radio streams.  This is another topic.  But to mention some good programs:  Rolly Recorder (akronedge.info/wintersoft), ghostrecorder (akronedge.info) and streamripper