Check out MSN user groups. Look up the car make and radio make and a good chance you'll find it. News groups for Peugeot got me my code when i lost mine!
Go to google and type in News or user groups and the either the make of car or radio. My Peugeot 405 has a standard peugeot radio, that's why i mention the car type. hope this is of some help.
Colm
February 2006