How can I change the size of the Wii screen on the tv?

We hooked up our Wii to our 59'; HDTV and the screen is cut off at the top and bottom. It makes it very hard to play Guitar Hero. Is there a way to change the screen size? If so how can I do it?How can I change the size of the Wii screen on the tv?
I believe in the Wii Settings you can change the size of the screen. On the main Wii Menu hit the circle with the word ';Wii'; on it to go into the settings. You hit screen resolution (I think that is what it is called) and change the size. You can also change the screen to be in HD if you haven't already done that.