It will be the Guitar Hero clone on PC but you can play your music files on the game like Audiosurf and Beat Hazard. I like this kind of games maybe this game could be good. Here is the website you can watch the trailer. It will come to Steam on 20th of July.
http://emerson.mh2o.com/index.php?p=about

Thanks for the info :) is it just the 4 keys?

Frets on Fire....but with Audiosurf and Beat Hazard elements....when are the preorders accepted?