A
podcast is an audio presentation that can be listened to through a computer or a portable media player. The term is a compression of the words
iPod (the most popular portable player) and
broadcast. Using services such as iTunes, listeners can subscribe to podcasts so that they automatically receive the latest feeds from podcasters. A variant of the podcast is the video podcast, also known as (you guessed it) the
vodcast.
More:
New York Times podcasts
NPR podcasts