First, add the -console command-line parameter to the shortcut for your game. Open the console in-game by pressing "~" (tilde). You can then type any of the following cheats:

Cheat - Effect
god (1) - God Mode On
god (0) - God Mode Off
giveall - 10,000 Coins, Max HP, Max Fuel
givemoney # - Get Money
truck # - Each # is a Different Truck
giveguns # - Each # is a Different Gun
map (1) - Reveal Map
teleport # - Teleport (#=Location)