MotoGP 06 cheats and cheat codes for Xbox 360

Unlock USA Extreme bike 
Go to the "Game Mode" screen, after press Right, Up, B, B, A, B, Up, B, B, A 

Unlock 50th Anniversary bike
In the "Season" option, set season to 2005.
Play with Valentino Rossi and win a Quick Race at Valencia

Unlock 50th Anniversary bike
In the "Season" option, set season to 2005. 
Play with Valentino Rossi and win a Quick Race at Laguna

Unlock Quick Race Extreme mode and tracks 
Play with Valentino Rossi and win a Quick Race in GP mode 

Unlock extreme mode 600cc-1200cc 
Repeat all the 17 tracks

Complete the following tasks to get gamerscore points:

Extreme Bike Collector (50 pts.) - Buy all extreme bikes 
Accredited (100 pts.) - All rider credits awarded 
Challenge Expert  (30 pts.) - Finish 50 challenges 
Challenge Master  (60 pts.) - Finish all challenges 
Unlock Extreme Mode Champion (10 pts.) - Won any extreme mode championship
Unlock GP Champion (60 pts.) - Won career mode grand prix season on champion diff.
Unlock GP Legend (100 pts.) - Won a career mode grand prix season on legend dif.
Unlock GP Professional (30 pts.) - Won a career mode grand prix season on pro diff.
Unlock GP Rookie (10 pts.) - Won a career mode grand prix season on rookie diff.

Unlock Extreme 600 - Legend (30 pts.) - Won a career mode extreme 600 season on 
legend diff.

Unlock Extreme 1000 - Legend (60 pts.) -  Won a career mode extreme 1000 season on 
legend difficulty 

Unlock Extreme 1200 - Champion (50 pts.) - Won a career mode extreme 1200 season 
on champion diff.

Unlock Extreme 1200 - Legend (75 pts.) - Won a career mode extreme 1200 season on 
legend diff.

Unlock Extreme 1200 - Professional (25 pts.) - Won a career mode extreme 1200 
season on pro diff.