Grand Theft Auto IV Unlockables

Misc Phone Numbers
How to enter cheats:

During gameplay press the button on the D-Pad to bring up Niko's mobile phone. Press again and you'll be able to see the phone's numbered buttons which are used to dial various numbers. Using the D-Pad toggle over the appropriate buttons in the same order, pressing to enter them. After you've the 10 digit code, the phone will automatically shift the cursor to the 'Call' button. Press again and it will activate the cheat.

Notes About Cheats:

Some cheats have the unfortunate side-effect of stopping certain achievements (future Entitlements) from being carried out, and you will be given a message saying the Achievement has been blocked when you activate the cheat. Cheats which are known to block wanted level will have a (*) next to it.
Number To DialUnlocks
4825550100Restores Niko's Health* (Cleaned the Mean Streets)
3625550100Restores Niko's Armour* (Cleaned the Mean Streets, Finish Him, One Man Army, Walk Free)
4865550100Weapons Cheat #1 - Baseball Bat, Handgun, Shotgun, MP-10, M4, Sniper Rifle, RPG & Grenades* (Cleaned the Mean Streets)
4865550150Weapons Cheat #2 - Knife, Molotovs, Handgun, Shotgun, Uzi, AK47, Sniper Rifle & RPG* (Cleaned the Mean Streets)
2675550100Removes Wanted Level* (One Man Army, Walked Free)
2675550150Increase Wanted Level by One
-Spawn A Car
3595550100Spawn an Annihilator
9385550100Spawn a Jetmax (Boat)
6255550100Spawn a NRG-900
6255550150Spawn a Sanchez
2275550100Spawn a FIB Buffalo (not a spelling mistake)
2275550175Spawn a Comment
2275550147Spawn a Turismo
2275550142Spawn a Congnoscenti (Mafia Car)
2275550168Spawn a SuperGT
3595550100Spawn a Police Chopper
4685550100Change the Weather/Brightness