Cheat mode:

At the main menu, highlight Options Mode and press Down, then press Left or Right until "Option: Cheat Codes" is selected. Press A and then enter one of the following case-sensitive cheat codes:

theworldismine          All locations 

greasemonkey            All car abilities 

hotwired                All cars in Arcade mode

                        (must be logged on to Xbox Live) 

bigbrother              Unlock 'Most Dedicated' stat  lovenotwar              Guns and rockets, press Left

                        stick and White to fire  zoomzoom4               Unlimited nitrous   howhardcanitbe(0-9)     Change difficulty (0 is easiest)

LAPD Car:

Beat all 5 L.A. Arcade circuit races.

Paris Cop Car:

Beat all 6 Paris Arcade circuit races.

Tokyo Cop Car:

Beat all 7 Tokyo Arcade circuit races.

Rocket Car:

Beat the game 100%.

Ghost Rider:

Using the Motorcycle, crash into somthing, then press start as you fall off the bike. press continue game, and you can ride your bike without a driver.

Thanks to Revolution readers PlanetOne, Matthew, armando villalpando, nirav, MarshaMarsha, and VRX!