The term podcasting derives its name from Apple’s iPod, —a portable digital audio player that allows users to
download music from their computer directly to the device for later listening. The term is no longer specifically related to the iPod but refers to any software and hardware combination that permits automatic downloading of audio files (most commonly inMP3 format) for listening at the user’s convenience.

Podcasting is a free service that allows Internet users to pull audio files (typically MP3s)
 from a podcasting Web site to listen to on their computers or personal digital audio players.
 The term comes from a combination of the words iPod (a personal digital audio player made
 by Apple) and broadcasting.                                                                              
Podcasting is delivering audio content to iPods and other portable media players on demand,
 so that it can be listened to at the user’s convenience.
The main benefit of podcasting is that  listeners can sync content to their media player and take it
with them to listen whenever they want to. Because podcasts are typically saved in MP3 format, they can also be listened
to on nearly any computer.

Podcasting is completed  in 4 Steps:-

1.Publishers create audio content, and post it to a web server, typically in MP3 format.
2.They publish an RSS file (newsfeed)  that contains RSS news items that reference the audio
 content. Each RSS item provides meta information about an audio file, such as the file’s name
 and description, and contains an RSS enclosure with the URL of the audio file.
3.End-users regularly check for new versions of the newsfeed, using an application like iPodder.
 When a new version is found, iPodder reads through it, identifies the audio file URLs, downloads
them and syncs them to a media player.
4.Users listen to the “podcasted” audio file when it is convenient.
Podcasting can be used for publishing any type of audio, and some developers are exploring the
 idea of using the same techniques to publish video and other types of content.

Podcasting is spreading quickly because of the rapid adoption of MP3 players, and the desire of
owners to have fresh content.