There's a bunch of non-Wii functionality in the You Rock. It can hook up to your PC or Mac (where it works with programs such as Garage Band, Sonar, and Finale), and can additonally link to your iPod, iPhone, or MP3 player, allowing you to "jam along" with your favorite Showaddywaddy tracks (yes, we know). You can even connect it to a guitar amp or mixer!
Alas, the peripheral's many functions mean it will launch in Q2 or Q3 with a price tag of $149.99. If you think you could get some use out of this besides playing on the Wii, that might make this worth it. While you wait, make the jump for the cheesiest trailer we've seen in forever.