At the controller selection screen press 'L1' to access the cheats you've acquired.
Perfect Game Points:
To throw a perfect game (which is worth a hundred points), just swap controls with the computer every time its team is supposed to be up to bat and strike out.
Be A Better Batter:
Right after the ball leaves the pitcher's hand you can pause the game and see where it's headed relative to the strike zone. While you still may not have enough time to move your cursor, you also won't swing at as many sketchy pitches.
Quickly Rejuvenate Pitchers:
In Season, Franchise or Expansion mode, put the unhealthy or weakened pitcher on the15 day DL. Next, take the pitcher straight out of DL and back into your lineup and he'll be healed!
Thanks to Revolution readers Mammajamma, Vulcanator, and Shesmydad!