Here’s some more Guitar Hero World Tour cheat codes.
Main Menu: select “Options”, “Cheats”, “Enter New Cheat”, then enter one of the following codes:
Performance Mode
Press Yellow(2), Blue, Red, Blue, Green, Red(2).
Hyperspeed
Press Green, Blue, Red, Yellow(2), Red, Green(2).
Auto Kick
Press Yellow, Green, Red, Blue(4), Red. The bass drum pedal will now be played automatically. Note: Enabling this code will disable earning any money after a song has been completed.
Unlock Quickplay
Press Blue, Blue, Red, Green(2), Blue(2), Yellow.
Aaron
Press Blue, Red, Yellow(5), Green.
Nick
Press Green, Red, Blue, Green, Red, Blue, Blue, Green.
Johnny Viper
Press Blue, Red, Blue(2), Yellow(3), Green.
Rina
Press Blue, Red, Green, Green, Yellow(3), Green.
Air Instruments
Press Red(2), Blue, Yellow, Green(3), Yellow.
Invisible Characters
Press Green, Red, Yellow(3), Blue(2), Green.
AT&T Ballpark
Press [...]

Here’s a few Rock Band 2 Cheat codes.
Unlock All Songs
Press Red, Yellow, Blue, Red(2), Blue(2), Red, Yellow, Blue to unlock all songs. Alternately, press Y, B, X, Y(2), X(2), Y, B, X on a controller. Note: This code also disables achievements and online features.
Select Venue Screen
Press Blue, Orange(2), Blue, Yellow, Blue, Orange(2), Blue, Yellow to unlock all venues. Alternately, press X, LB(2), X, B, X, LB(2), X, B on a controller. Note: This code also disables online features.
New Venues
Press Red(4), Yellow(4) to unlock new venues. Alternately, press Y(4), B(4) on a controller.
Awesome Detection
Press Yellow, Blue, Orange, Yellow, Blue, Orange, Yellow, Blue, Orange. Alternately, press B, X, LB, B, X, [...]