Instructions
Insert a PS2 memory card and the Gameshark disc, then turn on the PS2.
Select the "Expert Cheat Mode" option in the main menu.
Select the game you will play from the list in the expert cheat menu with the "Up" and "Down" buttons on the D-pad. Press the "Right" button to move to the cheat menu for your game.
Press "Circle" in the cheats list to access the options menu. Select the "Add" option with "X."
Enter a description for your cheat code by using the on-screen keyboard. When you're finished, select the "Enter" option to return to the cheat menu.
Select the cheat description you just created and press "Right" on the D-pad. Press "Circle" on the next screen, then select the "Add" option.
Enter your code using the on-screen keyboard, and select "Enter" when you are done.