Rocksmith, it's like guitar hero but with an actual guitar

So I came across a new game by Ubisoft named Rocksmith whilst searching the internets. It is similar to Guitar Hero and Rock Band. Only with this game you can actually plug in your own guitar and not use the little plastic things they gave you in the likes of Rock Band etc... It is released for PC, PlayStation and Xbox on 18th October later this year. I think Rock Band attempted something like this only with a quite expensive 'pro guitar' you had to buy from them. The game comes with a 50 song soundtrack which is a pretty decent start and contains songs from: The Black Keys, Nirvana, Rolling Stones, White Stripes and Stone Temple Pilots to name a few. If they do anything they should and hopefully will widen the range of songs you can actually play, though downloadable content. I will definitely be giving it a shot, it seems a great idea. I don't really know how it will know what you play, it must have a sensor that tells the game what note you play or something. So I'm guessing it will need to be perfectly tuned, which leads to the assumption that the game will also have a built in tuner between the game and whatever guitar you have plugged in.