Fireworks:
Hit a home run with the home team in Fenway Park during a night game and you see fireworks.

Batting Cursor:
On rookie mode, when you bat, hold the analog slightly in any direction and the batting cursor will automatically follow the ball.

Harder Throw:
On defense, right before the computer catches the ball, press the direction of the base you want to throw to and A to have a harder throw.

Dream Stadium:
To be able to get the special field dream stadium you have to hit three balls into the cove in the pacific bell stadium where the san francisco giants play baseball. The code will only work if you do it on a single player game.

Maximum Player Creation Points:
To be able to create a player with maximum stats, just complete a season and win the world series. Not sure how long the season has to be, but it was done in a 52 game season with three inning long games as the Orioles. Then go create a player and have fun with him.

Bunting:
Press L to bunt.

Super Fast Ball:
When pitching with Pedro Martinez press pause and then press R, L, Left, Right.

Stupid Computer:
In Rookie mode, with two strikes on the batter, pitch a high fastball way out of the strikezone and 90% of the time, the computer will be stupid enough to swing at it and miss for strike three.

Thanks to Revolution readers AEagleDude16 (Phil), T.Killa, Brett Conner, Matt Everett, chris, derek cuneo, mike and Ruvi "The Kid"!