Grooveshark is a streaming service that allows you to pick any artist, song or album and simply create playlists to listen to on your computer, tablet or phone. Unlike Pandora or IHeartRadio, it does not give you new artists/songs based off of your listening preference. Instead, it's more like just streaming the music you want to hear with no experimentation.
The HTML5 site works well enough on Windows Phone for streaming in IE9 but Grooveshark have stated they have no intentions for a dedicated client for Windows Phone. That's too bad. However, the developer of MetroRadio (an unofficial Pandora app for Windows Phone) is now working on Groovyshark, an unofficial Grooveshark client for our devices.
We took the alpha build (i.e. pre-beta) for a test drive just to show you that indeed you can hook-into Grooveshark. We also got a sneak peek at the new "screensaver" function that's coming to MetroRadio too which is very reminiscent of Zune's music player on the Zune HD and Zune Desktop. That latter feature is something many have wanted Windows Phone to have built in so it's nice to see someone is working on it.