Press L at the controller selection screen. This will activate cheats that you have already bought.
Different Homerun Replay Angles
When you see your batter running home from the third base, press any button, except A, to see different camera angles.
Refill Pitcher's Energy
In any mode, go to the DL list, and put any pitcher on the 15 day DL. Then take him back into your lineup and he will have refilled all his energy.
Secret Stories
Start any game and do not press any buttons. A few minutes after the lineups and the starting pitcher are announced, Thom Brennaman will start telling stories about baseball.