Set Speed
Hold UP + R while in a car to set the speed without pressing the gas.

Display Coordinates
Press Start + A + B during game play.

Police Bribes
For every ten vigilante missions completed, you will get a police bribe at your hideout. The maximum number you can get is six.

Easy Money
Kill the people on the streets with big yellow coats. They usually drop about $1,000 each.

Package Rewards
You can get these items by collecting Hidden Packages:

Body Armor: Collect 30 Hidden Packages
Shotgun: Collect 40 Hidden Packages
Grenades: Collect 50 Hidden Packages
Molotov Cocktails: Collect 60 Hidden Packages
Assault Rifle: Collect 70 Hidden Packages
Pistol: Collect 10 Hidden Packages
Uzi: Collect 20 Hidden Packages
Mini Gun: Collect 80 Hidden Packages
Rocket Launcher: Collect 90 Hidden Packages