All you have to do is dial these into your phone.

Health
482-555-0100

Armor
362-555-0100

Weapons #1
(Baseball Bat, Handgun, Shotgun, MP5, M4, Sniper Rifle, RPG, Grenades.)
486-555-0100

Weapons #2
(Knife, Molotovs, Handgun, Shotgun, Uzi, AK47, Sniper Rifle, RPG)
486-555-0150

Remove Wanted Level
(Blocks achievement "Walked free")
267-555-0100

Raise Wanted Level
267-555-0150

Change Weather/Brightness
468-555-0100

Spawn Annihilator
359-555-0100

Spawn Jetmax
938-555-0100

Spawn NRG-900
625-555-0100

Spawn Sanchez
625-555-0150

Spawn FIB Buffalo
227-555-0100

Spawn Comet
227-555-0175

Spawn Turismo
227-555-0147

Spawn Cognoscenti
227-555-0142

Spawn SuperGT
227-555-0168

Complete Map - (with weapon, health, armor, pigeon, etc. locations)
Enter the URL "www.whattheydonotwantyoutoknow.com" into computers in the game