Strategy Informer  

24: The Game Cheats & Codes

Cheat Codes for the "Security Clearance" Menu
At the main menu, hold down all four shoulder buttons (L1+L2+R1+R2) at once, for about 3 to 4 seconds, until the "Security Clearance" cheat menu pops up.
To enter the letters for the codes, hold down the X button over the character you wish to change, then move the + button left or right to change the characters, then let go of the X button to move to the next character using + button. Once all the characters are entered in correctly, press the Square button, and the cheat code should turn orange.