At the main menu, select the "Extras" option, then choose the "Cheat Codes" option. There are four boxes with pictures in them. Line up the pictures in the correct order by scrolling through them, then choose "Enter Code" to activate the code.
Enter Baseball, Baseball, Baseball, Shirt as a code.
Enter Baseball, Bat, Bat, Baseball as a code.
Enter Hat, Helmet, Helmet, Hat as a code.
Enter Hat, Glove, Glove, Hat as a code.
Enter Glove, Glove, Helmet, Helmet as a code.
Enter Bat, Bat, Hat, Hat as a code.
Enter Hat, Hat, Shirt, Shirt as a code.