At the player name screen, enter your name as "theshit" without spaces. Then start a level ( not "resume saved status" or it will not work ). When the level starts you will have all weapons with semi-infinite ammo. (Note: If you are busted by the cops or die in any way then you lose all the weapons and ammo).
Cheat Codes
BIGGUNS - All Weapons
SESAME - Open ALL Levels
INFINITY - Infinite Energy
LAWLESS - No Police
BADBOYZ - Start with Maximum wanted level
BOYAKASH - Start with Multiplier at 5X
ULTIMATE - Start with 10,000,000 cash
DBLWAMMY - Infinite "Double Damage" Powerup
BIGFRIES - Infinite "Electro Gun" weapon
TOASTIES - Infinite "Flame Thrower" weapon
SCOOBYDO - Infinite "Invisibility" powerup
WOUNDED - Blood Splats ON
ALLFREND - Max respect from each gang
ERRHUH - All pedestrians are Elvis
BIGCATS - 99 lives
LOSTTOYS - Keep weapons after death
Elvis Trick
Drive around in a car,truck, or bus(the best kind to do it wit is a cop car or a z-type) until you see the Elvis impersonters. With out scaring them off, try to run them all over at the same time. If you did it right the screen will say ELVIS HAS LEFT THE BUILDING! By doing this you will recieve lots of money.
Quick multiple cheats
If you would like to access more than one cheat at the same time than after entering your cheat on the name screen exit the name screen and go back into it again, delete the previous name and enter another cheat, and repeat the same routine untill have done all your cheats.
Ride a train
For a fast way to get around the cities, go to a train station. When a train stops press Car Jack to hop in the train.