Unlock Cheat Menu:
At the Title Screen, press Circle (5x) then Square (4x). If done correctly you'll hear a sound. Now in the Special Features menu, it will allow you to toggle cheats on and off.
Unlock Bin Laden Look-alike Enemies:
Play the Afghanistan-Pakistan Border mission. Pause the game and press Circle, Circle, Circle, Square, Square, Square. Now you may encounter enemies who resemble Bin Laden.