At the title screen, press Circle(5), Square(4). If you entered the code correctly, you will hear a sound. Select the "Special Features" option to access the cheats, which can now be enabled individually before starting a game.
Unlock Cheat Menu
If you play this game anything like me, your gonna have a hard time beating it. On the title screen, press circle 5 times and square 4 times. Do it fast and you should hear a sound confirming the code. Now before you start the game, go to special features. You will now be able to access the cheat menu.
Unlock Bin Laden
To unlock someone who looks an awful lot like Osama Bin Laden, play the Afghanistan-Pakistan Border mission. Pause the game and press CIRCLE, CIRCLE, CIRCLE, SQUARE, SQUARE, SQUARE. This will make every few enemies look like Bin Laden.