Soundflavor DJ is a new iTunes music companion that shipped yesterday.

It's designed to help music lovers build playlists and find new music that is based on the music that they like most. It also helps users with burgeoning digital music collections remember music they actually own but have forgotten about.

If a user plays a song or playlist in iTunes, Soundflavor DJ can also play other songs from a library that are similar, including some a user may never have expected would fit with the original choice of track(s).

When songs are played they immediately appear in the Soundflavor DJ PlayStream. Users can adjust settings to determine how often the software makes song recommendations.

The built-in Music Recommendation Engine that has been developed over six years. To create the engine, the company analysed hundreds of thousands of songs from across multiple genres.

The solution was built in collaboration with a firm called Adaptive Path, a product design and user experience company that has previously been involved in helping create Flickr, Blogger and BitTorrent.

The Windows XP version of SoundFlavor DJ is available now, with a Mac version "planned", the company said.

While they wait, Mac users can try another music recommendation service, called BeaTunes.