NBA: In The Zone 2 Codes -

All-Star Team:
Highlight "Start" on the title screen and hold L1 + R2 + Select + Start until screen fades. The All Star Team may now be selected in exhibition mode.

Extra players:

Magic Johnson
Create a new player and select model number 25.

Larry Bird
Create a new player and select model number 29.

Michael Jordan
He is already on the roster and named "M.GUARD" on the Bulls.

Shaquille O'Neal
He is already on the roster and named "S.CENTER" on the Lakers.

Charles Barkley
He is already on the roster and named "C.FORWARD" on the Rockets.