To make yourself appear in color while everyone else is black and white, enter DUOTONE as a code.

Unlock Bonus Teams
Enter Gameplay in the Options menu. Once there, Hold D-pad Left + Left Analog-stick Right and press BACK. The "Codes" selection will now be unlocked at the options menu.

Enter MEGASTARS as a case-sensitive code to unlock the Sega Sports, Visual Concepts, and Team 2K2 in exhibition and street modes.

Unlock Trash
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.