Cheat Codes for All Star Baseball 2003:
Enter the code for the desired cheat:

Cheat menu - Press L at the controller selection screen to activate cheats that have been bought.

Alternate Uniforms - Hold L + R

Taunt opponents - Hit a homerun and on the way to third (after replay), press L or R

Hidden Commentary - While looking at the credits press A to hear commentary about the developer who is currently on the screen.

Credit commentary - Press A during the credits to hear commentary about the person currently featured.

Easy Trivia Wins:
When a question is presented, press B once and the game will ask you if you want to quit. press B again to continue the game. Now press A, and it will move you on to the next question.