I just downl.. got this game, it looks like Guitar Hero, but less fun.
http://www.gamekult.com/video/8058101
Not very realist, since you can't create your own chords, but the effect stuff is fun. On the opposite, the songs given to play are really really deep shit, like Bob Marley, Nirvana, not really entertaining. Another lack is that to obtain a good succession of chords and a fluid sound, you have to destroy the screen by smashing the pen very hard on it, and it doesn't sound perfect anyway. But the recording mode is kinda cool, and it's a good thing that musical games appear on several machines.