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. The cheat options include "Invincibility", "Infinite Ammo", "All Fugitives", and "All Weapons".
Pause the game during the Afghanistan-Pakistan Border mission, then press Circle(3), Square(3). Enemies will randomly appear as Osama Bin Laden. Note: They will still be normal in every way except appearance, and will not be a Boss opponent.