If you are a Last.fm user then this application which is currently in development could be of interest to you. Last.fm Mobile in its Pocket PC version has scrobbling and radio functionality, and the Smartphone version is limited to scrobbling from Windows Media Player - but it works perfectly.

Using a unique music recommendation system known as "Audioscrobbler", Last.fm builds a detailed profile of each user's musical taste by recording details of all the songs the user listens to, either on the streamed radio stations or on the user's computer or portable music device.

This information is transferred to Last.fm's database ("scrobbled") via a plug-in installed into the user's music player. The profile data is displayed on a personal web page. The site offers numerous social networking features and can recommend and play artists similar to the user's favourites.