This game is also available on PC.
Press Triangle, Square, Circle, Square, X at the main menu.
Gold medals:
Press Circle, X, Triangle, Square at the main menu.
Gold in Sprint event:
Press X, X, X, Circle, X, X, X at the event selection screen.
Gold in Javelin event:
Press Circle, Square, X, X at the event selection screen.
Gameshark Codes
Have Gold Medal In Every Event
50000c040000
80016d640006
All Olympic Training Complete
50007e020000
800165e86464