In a nutshell, podcasting is the relatively new phenomenon of publishing media files--usually MP3s--so that they are available for download to anybody who subscribes to them. A typical podcast is a talk radio show, recorded so that you can listen to it when it's convenient for you. The underlying transport technology is no different from an RSS newsfeed, except that you listen to the feed rather than read it.

Using one of the many free podcast aggregation/reader applications, such as iPodderX, iPodder or the podcast features in iTunes, you can subscribe to any of thousands of podcasts, and content will be downloaded invisibly as it becomes available. These applications work seamlessly with iTunes (and well with other jukeboxes), so you'll get your latest podcasts automatically if you autosync your iPod. Of course, you can listen to podcasts on any MP3 player, not just Apple models. The PSP's RSS channel feature can also be used to listen to audio podcasts, though video podcasts currently won't work on Sony's handheld.