Apple says the next version of its iTunes music management program will give people a way to find and subscribe to podcasts, MP3 audio files online.

Podcasts are downloadable "radio shows" that can be created and listened to by anyone with the right equipment.

Listeners subscribe to shows for free, the latest of which is sent automatically to digital music players.

Free programs have been built to do this already, but now Apple says iTunes will have this function built in.

"With the next version of iTunes, due within 60 days, there will now be an easy way for everyone to find and subscribe to podcasts", Apple said in a statement.

Apple chief Steve Jobs was demonstrating the functionality at a technology conference in the US.

The demo showed how the program lets people access, organise and sync-up podcasts to any digital music player.

Including this functionality into iTunes opens up the possibility of selling podcasts, just like music.

Podcasts have grown quickly in popularity with many of the millions of portable digital music player owners who want to listen to a range of audio, not just music.

But they have also become popular because anyone with a microphone, computer, software and a net connection, can produce one themselves.

Their rising popularity is challenging conventional radio's broadcasting and business model. As a result, many radio stations globally are making their shows available as podcasts too - in downloadable MP3 format.

The BBC recently made 20 radio broadcasts available as podcasts, and several radio stations in the US, including the digital radio network Sirius, use podcasts as part of their broadcasts.

US politicians are experimenting with podcasting after finding success with blogs during the presidential elections. Virgin Radio has also made talk-based segments of its breakfast show available as podcasts.

iPod not necessary

Despite its name, podcasts are not exclusive or tied to iPods in anyway.

Currently, people who want to listen to the thousands of podcasts that are available - from fishing shows, work-outs, comedy sketches, to gadget news - use third party programs, such as iPodder.

Listeners can tell the program details of the shows they want to listen to. This usually comes in the form of a "feed" URL.

The iPodder, or similar application, detect the links to the shows and automatically download them.

People can then use music jukebox applications, such as Windows Media Player or iTunes, to send the most recent files to music players once connected to a computer. This is called "auto-syncing".

Podcasting is seen as an example of "time-shifted" content. This is a buzzword in the technology industry which describes taking digital content and playing it when and where you want.

The BBC is currently trialling its own multimedia jukebox program, called the Interactive Media Player (iMP).

It lets people catch up and download TV and radio programmes they may have missed up to seven days after they have been broadcast.