Unlock Hidden Tracks

To unlock some other tracks right from the beginning, do the following. From the Main Menu select Options.
On the Options screen press and hold X and Y.
You'll notice a new selection on the screen called Passwords.
Without letting the X and Y buttons go select Passwords.
Once you've done that you can enter in one of the following Passwords to unlock tracks.
All passwords are Cap sensitive.

CinqueValvole	Unlock the Fiorano course
LiebeFrauMilch	Unlock the Nurburgring course
Stars&Stripes	Unlock the Laguna-Seca course
KualaLumpur	Unlock the Sepang course
DaysofThunder	unlock the Atlanta course