Start a game then press pause and enter the following

All camera views - L1 + Triangle, Left(2), Circle, L1 + Triangle, L1 + X, Select.

Flapping hop mode - R1 + Left, Left, L1 + Triangle, L1 + Up, Select

Floating hop mode - R1 + Left, Left, L1 + Circle, L1 + Triangle, Triangle, Select

Full turbo - Triangle, Up, Right, R1 + Square, L1 + Circle, Select

Infinite turbo - L1 + Right, R1 + Down, R1 + Left, L1 + Right, R1 + Down, L1 + Right, Triangle, Select

Lock camera - Circle, L1 + Triangle, L1 + X, Left, L1 + Circle, Circle, R1 + X, Select.

Race at high speed - L1 + Right, R1 + Down, Square, L1 + Triangle, R1 + Down, L1 + Left, Select

Recharging turbo - R1 + Right, L1 + Left, L1 + Triangle, Left, Select

Rolling camera - Circle, L1 + Triangle, L1 + X, Right, L1 + Circle, Left(2), Select

Skip a lap - Left, L1 + Triangle, L1 + Up, Select

Turbo air mode - Right, L1 + Circle, Circle, R1 + X, L1 + Left, Triangle, Select

TV camera - Circle, L1 + Triangle, L1 + X, Triangle, R1 + Up, Select.

 

Enter the following at the main menu

Unlock everything in the game - L1 + Left, R1 + Up, L1 + Left, Right, L2 + Triangle, Triangle, R1 + Right, L1 + Right, R1 + Down, R1 + Triangle

All racing tracks - right, L1 + Triangle, Circle, L1 + Left

All seasons - Square, L1 + Left, L1 + Triangle, Square, Circle, R1 + Down, Square to unlock all seasons

All stunt tracks and stunt mode - Square, Triangle, Up, R1 + Down, Triangle

All tracks - L1 + Triangle, Left(2), Triangle, Right, L1 + Triangle, 

Next difficulty setting and season - L1 + Circle, L1 + Circle, R1 + Right

 

Stunt mode 
Collect all of the ten track coins in Season Mode and you will unlock stunt mode (one or two players).

Race as Granny!?
Finish the game in first (with any racer) on the professional difficulty.