(last update - Oct 12 2010)
Total current cheats: 1
print meCheat Menu
Simply go to the Title Screen and press this combination on the phone:
Up, Down, Up, Down, Left, Right, Left, Right, 5, 7, 5, 7
You'll notice that probably nothing happens "instantly", but when you are playing, you can go to the Pause Menu, and you'll see "Cheat" under "return to game", This allows you to earn money, travel to a specific level, get the "God Mode" and another things.