Enter the options menu and select "Gameplay". Hold D-pad Left + Left Analog-stick Right and press Start. The "Codes" selection will now be unlocked at the options menu.
Enter "MEGASTARS" as a case-sensitive code to unlock three bonus teams.
Enter "DUOTONE" as a case-sensitive code to have your player in color with all other players in black and white.
Enter "SPRINGER" as a case-sensitive code to see trash in the streets. Note: This does not work in the gym.