Press L1, R1, L2 and R2 (in order, not all together, while at the main menu). You will get the message "Poof! Everybody is a kaadu!" While you are racing, all the racers turn in to Nabooien Kaadu on flying tread mills.
Infinite turbo booster
On the main menu, press L1 R2 L1 R2 Square Select.
Race Backwards
At the Main Menu, press L2, L2, L2, L2, Circle, Select.
Secret racers
To unlock secret racers, win the Golden Cup in the Galaxy circuit race as Anakin.
Super Honk
At the Main Menu, press Circle, Circle, Circle, Circle, L2, Select.
Switch Language to Battle Droid
At the Main Menu, press Select, Select, Select, Up.
Switch Language to English
At the Main Menu, press Select, Select, Select, Circle.
Switch Language to French
At the Main Menu, press Select, Select, Select, R2.
Switch Language to German
At the Main Menu, press Select, Select, Select, L1.
Switch Language to Italian
At the Main Menu, press Select, Select, Select, L2.
Switch Language to Jawa
At the Main Menu, press Select, Select, Select, Square.
Switch Language to Spanish
At the Main Menu, press Select, Select, Select, R1.
Unlock Boba Fett
In order to play as everyone's favorite bounty hunter, tap Square, Circle, Triangle, Circle, Square at the main menu. You will then get a message saying that Boba Fett has replaced your racer. Then start the game as normal, select your character, and you will be playing as Boba Fett as soon as the race starts. Next select your character as normal, and when the race starts you will be playing as the Tank.
Unlock Galaxy Circuit
First, play through each individual race and finish in the top three in each track. After that, the Galaxy Circuit will become available.
Unlock Mirror Tracks
Complete the Galaxy Circuit with any character and receive a gold medal.
Unlock Trade Federation Battle Tank
To race as a squished version of a Trade Federation Battle Tank, press Circle, Triangle, Square, Circle, Triangle, Square at the main menu. You will then get a cheat confirmation message. Next select your character as normal, and when the race starts you will be playing as the Tank.