Unlock Madden Van:
     Have a saved game from Madden NFL 06 on your memory card.

Unlockable Cars:

Black Elite Racer:      Achieve Elite Rank.
Criterion GT Racer:     Finish the White Mountian Challenge.
Custom Classic:         Finish the Sunshine Keys Challenge.
Dominator Assassin:     There must be a Burnout 3 game save 
                        on your memory card.
EA GT Racer:            Finish the Central Route Challenge.
Etnies Racer:           Finish the Motor City Challenge.
Euro Classic LM:        Finish the Eternal City Challenge.
Hot Rod:                Finish the Lone Peak Challenge.
Logitech World Racer:   Finish the Rank 10 Ultimate Revenge GP.
Low Rider:              Finish the Angel Valley Challenge.
Nixon Special:          Finish the Eastren Bay Challenge.
Revenge Racer:          Finish 100% of the game.