NBA: In The Zone 2000 Codes -

Big heads:
Select the "New Season" option at the main menu, then press L1, R1, L1, R1, Circle, Square.

Super player:
Enter the settings screen and select "Rosters". Create a player and copy Kobe Bryant. Change his statistics to 6'9", 225 lbs., and rename him Kenyon Martin. This player can make any reasonable shoot.

Dunk contest moves:

One-handed Dunk: Press , during your run up, then press .
Back Jump: Quickly press , , during your run up, then press .
Back Change: Press , during your run up then press .
Power Dunk: Press (x2) during your jump.
Clutch Dunk: Press , during your jump.
360 Slam Dunk: Quickly press , , , , during your run up then press .

Special moves:

Back Change and One handed Slam
Press , , during your run up then press . Press or during the jump at about the freethrow line.

Back Jump and Clutch Dunk:
Quickly press , , during your run up, then press . Press , while in the air.