Chances are you've probably never heard of it, but six million Americans - one third of iPod users in the US have at some point downloaded and listened to a Podcast.

According to a survey carried out by the American research company Pew Internet & American Life Project the survey questioned over 2000 people. Extrapolating this results out to the American public and you get over six million Americans likely to have downloaded a podcast at some point in the last year.

Podcasting, named by combining iPod and broadcast are audio files that can be downloaded at any time and listened to on any Mp3 player.

You can now get a pod cast of virtually any subject from technology reviews to church sermons - a quick search on Google brings up 3,810,000 results, with the main site being a website dedicated to listing podcast. The site currently has over 4000 podcasts available to download and listen to.