A podcast is an audio file that you download from the Internet. After you download it, you can listen to it on your computer or on an MP3/portable music player. It is an ideal tool to improve your listening skills especially when you are on the go.
The podcasts on these sites will help you to improve your English vocabulary and pronunciation and your listening skills. They are quite short (5 or 6 minutes) and delivered in clearly spoken English. Many of them are linked to grammar and vocabulary notes, or to exercises or quizes: