In the game create a new profile, the goto EXTRAS. Here you can type in the codes:

GIVEALL        Unlock all tracks
GIEVEPIX       Get all normal cars and adds 1000000 in credits
RAIDERS        Get the Icecreamtruck
ELPUEBLO       Get the Eldiablo car
KALJAKOPPA     Get the Rocketcar
GIEVCARPLZ     Get the Schoolbus
BIGTRUCK       Get the Pimpstercar
WOTKINS        Get the Flatmobile
RUTTO          Get the Pimpstercar