A new software application that plays DJ with your iTunes library, Tangerine, has been revealed by the Potion Factory.

The Mac OS X 10.4-only software is available now in beta. It lets users create playlists by analysing the BPM and beat intensity of the songs in their iTunes library.

"We came up with the idea after I noticed that I was spending a good 30 minutes to come up with about 30 tracks for working out. I would repeat the process fairly often and I was getting tired of it and tired of listening to the same songs over and over again," the developers explain.

There is a limitation to the application - it cannot analyse songs purchased from the iTunes Store because of the digital rights management (DRM) technology FairPlay.

The major labels demand DRM be placed on tracks sold through online services, restricting interoperability and use of legally acquired media.

Testers who send the developer a useful bug report will be given a free licence for the release version of the application when it ships.