Press the 'Back' button in any level where you can get a pearl and it will take you to the 'Controller' screen. Hold the Left trigger and enter the following codes for the corresponding effect. After you have entered the codes release the Left trigger and you will get a confirmation message telling you the cheats have been activated.

Creatures Fly off the Screen when Touched:
X, X, X, X, A, X, X, X, X.

Replace Pearls with Coins:
X, A, X, X, X, A, X, X.