Podcasting is a new way of listening to radio shows and you don't have to own an iPod or a radio to do it.
You can get a podcasted show sent to your computer automatically so that you can listen to the show at a time that is most convenient to you.
When you subscribe to a podcast, it will automatically download to your computer whenever a new show is produced, allowing you to decide when and how you choose to listen.
The internet has opened a whole world of choice to radio listeners, allowing them to tune in to stations from all over the world that accomodate even the most obscure musical tastes. But many people don't really enjoy listening to internet radio for too long while they have to sit at their desk and stare at their computer monitor.
The aim of podcasters is to free the listener from their PC and from the whims of radio schedulers.
If you have an mp3 player you can put the podcast on your player and listen to it wherever and whenever you like.