Enter your name as the following, then select the "Cheats" option on the main menu:

STRANGE 	to drive a bus 
PEUGEOT 	to drive a Peugeot 
MIRROR 		to get mirrored tracks 
_MONEY_ 	loads of money 
THRILLS		Dual Shock controller goes nuts
FFSA 		Rally Jeunes mode
 

Thanks to Revolution reader Jeremy Clifton!