There's nothing I hate more about the Guitar Hero series than having to play through all those boring songs in career mode to unlock the good songs they hide in the bonus section. In guitar hero 3 it's even worse - there are "boss battles" you have to beat between sections of songs or you can't move on. After trying and failing to out-shred the first boss, Tom Morello, about five times I scoured the intertubes for a way to beat him - and found something even better! The unlock all songs code:

Codes for GH3 are entered on the Cheats menu under the Options menu. You need to strum the notes when you enter a code.

Unlock All Songs: (YO) (RB) (RO) (GB) (RY) (YO) (RY) (RB) (GY) (GY) (YB) (YB) (YO) (YO) (YB) Y R (RY) R Y O

via The ScoreHero Forums