Instructions
Insert your "Grand Theft Auto" disk into your PlayStation 2 and start the game.
Enter a cheat code, such as those found on GameSpot and similar websites. Some popular codes include "R1, R2, L1, X, Left , Down, Right, Up, Left, Down, Right, Up," in order to enable $250,000, full health, body armor and vehicular repair. You can also make cars fly by entering "Square, Down, L2, Up, L1, Circle, Up, X, Left."
Play the game with the mods. When you turn the game off, the mods will go away. You can re-enable them during the next gaming session by entering them again.