There is another gathered info around net on Guitar Hero III cheats & tips
CHEATS!!!
All Items Available
To make every item available at the in-game store, insert the following lengthy cheat at the in-game cheats menu. Keep in mind that because you’re strumming using four buttons, no sounds will play. You’ll have to check the store when [...]

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These tips and tricks come from searching through the net. let me know if there is any new ones you have discovered or if you know any we [...]

Adjusting Wiimote Volume/Rumble:
Hit Menu on any screen, click the Wii Remote Settngs on the bottom. You can now adjust Remote Volume, Vibrate.
You can also reconnect a controller if you need to change batteries or have to blame something for your lousy bowling (hehe).
Rearranging the Main Menu/Channel screen:
Just hover over the channel you want to [...]