Unlock all songs, guitars and outfits in Guitar Hero 3 for PS2, PS3, Wii and XBox 360.
Go to Options > Cheats > Enter Cheat. Then play the following 4 note chords.
G=Green, R=Red, Y=Yellow, B=Blue, O=Orange
GR_BO
GRYB_
GRY_O
G_BYO
GRYB_
_RYBO
GRYB_
G_YBO
GRYB_
GRY_O
GRY_O
GRYB_
GRY_O