Podcasting
The word 'podcast' was a portmanteau of Apple's iPod and the word 'broadcasting'.
Source: Apple Computer, Inc. 
Podcasting is the popular name of a method for automating the distribution of video and audio files over the internet, commonly via RSS (Really Simple Syndication).
Using podcasting, it is possible for a content owner – called a podcaster – to distribute a regular (such as daily or weekly) or irregular program to the computers and mobile devices of subscribers to view or listen to.
The word ‘podcast’ was invented from a combination Apple Computer's iPod 
music player, and the word broadcasting. Podcasting does not require an Apple iPod or Apple software to use.
Podcasting has become a very popular way to ‘push’ radio and other video and audio content to people who cannot watch or listen to shows at the times they are live on commercial or public broadcasters.
It has been particularly successful for distributing shows such as documentaries, educational information, independent music and movie previews. It has not been as successful for delivering ‘time-sensitive’ content such as news and sports – where people like to listen or view them as they happen.
How podcasting works
In podcasting, a broadcaster develops audio and video shows in a format suitable for distribution over the internet (such as MPG3 audio or MPG4 video). These files are uploaded to a publicly accessible computer connected to the internet.
The broadcaster also creates a ‘feed’ file that provides details of the shows including their address on the internet, name, synopsis, creator and other information in a format that can be understood by software programmes called ‘podcatchers’. The format often used is RSS; however, other formats can also be used. The feed file is also uploaded to a location on the web with a unique web address or URL.
People interested in viewing or listening to podcasts can download a free podcatcher program and type in the web address of the show feeds, in effect subscribing to the shows.
The program tracks the web addresses and when the feeds are updated with new shows it automatically downloads the new show files.
These shows can then be transferred to a mobile device, such as a MPG3 player, or viewed and listened to on the person’s PC.
Who is podcasting?
Because of how simple it is to podcast, many people at home and small businesses have had a go at Podcasting. However, large companies and broadcasters have also become podcasters.
For example ABC Radio began a podcasting service in May 2005. By March 2006, more than 350,000 podcasts were being downloaded each week. ABC Radio now offers podcasts for more than 83 programs .
To find podcasts, special directories have emerged on the internet. These provide a list of many of the most popular podcasts now available. Directories include: