Easier Homers:
While at bat hold the analog stick up/left and then press B.

Automatic 3 Outs:
During gameplay, press and hold:
L+R+Z and then press down and up.

Homer Noises:
After Hitting a homer press one of the following to hear various noises:
C-Up, C-Right, C-Down

Get an Extra Run(VISITING TEAM ONLY):
During gameplay, enter the following:
L+R+Z and press C-Right, C-Right

Get an Extra Run(HOME TEAM ONLY):
During gameplay, enter the following:
L+R+Z and press C-Left, C-Left

Automatic Three Ball Count:
During gameplay, enter the following:
L+R+Z and press up, down