Podcasts are audio or audio/video files that can be downloaded to a computer or MP3 player. They use RSS feeds to make users aware of new files.
Podcasts from onestopenglish include:
Live from London (interviews with members of the public out and about in London, Oxford and Edinburgh.)
The Road Less Travelled (a soap opera)
The Space Invaders (an intermediate level audio serial)
The Well (a beginning level audio serial)