Podcasts (audio that can be downloaded and played on the iPod) have redefined the listening experience. Not only can you find thousands of very specialized content'from audio books like Speak French in Thirty Days to stand-up comedy routines to the latest song from a bluegrass band'but you can customize your playlist, and choose exactly when you're ready to hear it. It's audio on the go.

Podcasts have been designed to play on the iPod, but the popularity has moved mobile phone manufacturers to allow mobilecasts. These are podcasts that are played on the cell phone. After all, cell phones have made great strides in terms of storage capacity and audio quality. Many ringtones actually parallel the kind of sounds you'd get while listening to the radio.

What's missing? High speed phone networks which could carry the information, and memory capacity. MP3 files can be too large for a standard mobile network to manage, so the podcast had to be reformatted for easier download. There's also the question of why people would want to hear a podcast on the phone. What kind of content streams would be interesting to them, enough to go through the extra hassle of reformatting a podcast file?

Several companies have risen to the challenge. They are creating podcasts specifically for mobile phones. One of the steps they have taken is to create shorter segments, usually on a very focused topic. Information is shortened into news snippets, or divided into chunks that people can listen to for a minute at a time.

Also, these companies reviewed the kind of information people would want to get from a mobile phone. The iPod has made it easy for people to download and play information'in fact, the convenience is one of the biggest selling factors. What would prompt them to use another medium, instead of just hearing it over their trusty pod?

Studies and surveys shows that there was a market for those who were very busy and needed immediate information, something that would help them in a pressing decision. The iPod is still largely seen as a product to relax with, and isn't always carried around. It can be left in an office drawer, or zippered into a gym bag pocket. But people always bring their cell phones with them. A mobile cast would then have to provide a kind of immediacy, a quick solution to a problem that can't wait. This could be a restaurant review (right before they decide where to have dinner), news headlines, or stock changes.

One of the big players in the mobilecasting industry is Melodeo, which introduced the Mobilcast application. Once installed in a mobile phone, it enables listeners to browse podcast catalogs. Pod2Mob also offers a service that lets people stream a podcast to a phone, using the WAP browser, and managing the files on the PC. Another company,

Juice Wireless, is also in the process of perfecting a technology that will let users create audio or video files and then stream it through the mobile network.