Update: Comments for this story confirm that using some of these cheats will not allow you to unlock certain achievements.
Having a tough time getting your revenge on in Liberty City? Thankfully Game Trailers user GhettoChild discovered the cheat codes in Grand Theft Auto IV for everything from restoring health to spawning an Annihilator helicopter. Using the in-game cell phone you dial the phone numbers to activate the code. While we haven't been able to confirm it, we assume using any cheats will no longer allow you to unlock any achievements and based on Rockstar's past with using codes, you may be unable to watch the final cinematic in the game.
Don't say we didn't warn you. Codes after the jump.