An audio or video file that is downloaded to a users computer (usally) automatically by using
RSS or Live Bookmarks.
When a users enters a website that is linked to a podcast, they may see one or two orange icons, they may see
xml or
rss or a little circle with lines comming out from it. The user can subscribe to
the RSS feed or "feed" by telling an RSS Reader to watch the RSS Feed and tell the user if there is an update, in which cast the user can download the Podcast.
The iTunes media player also has Podcast and RSS support built in, the user can go onto the "Podcast Directory" and select as many or as little podcast feeds as he or she wants. There are also other Podcast readers such as "Democracy TV".