Cheats for Call of Duty: Modern Warfare 3 for PC

When typing in your name, press shift and ^ and then a number. It will delete the symbol you just wrote, and change the color of your username. The colors are:

Once you hit level 20, use the Specialist package.
Make a class, give it hardline and use the Specialist package. It not only gives you extra points at kills 1, 3, 5, and 7 but also helps you complete the perk's challenges AND the Specialist Challenges for each perk.
You are completing the perks and each perk has a Specialist perk challenge to it. For example, if at 1 kill you unlock Assassin, you are completing Assassin Challenges while also completing the Specialist Challenge entitled 'Assassin.'
This equates to a boatload of XP once you start moving through these challenges. Not to mention the 200 XP per kill at kills 1, 3, 5, and 7 every time. You will be hard pressed to find a faster way to gain XP while playing any kill heavy mode.
You get EXTRA points for kills 8, 9, 10 etc. as long as you have all the perks on and have not died so it's like double XP in on itself.

• 3 Kills - UAV
• 4 Kills - Care Package
• 5 Kills - Intelligent Munitions System
• 5 Kills - Predator Missile
• 5 Kills - Sentry Gun
• 6 Kills - Precision Airstrike
• 7 Kills - Attack Helicopter
• 9 Kills - Strafe Run
• 9 Kills - AH-6 Overwatch
• 9 Kills - Reaper
• 10 Kills - Assault Drone
• 12 Kills - AC-130
• 12 Kills - Pave Low
• 15 Kills - Juggernaut Armor
• 17 Kills - Osprey Gunner

• 4 Kills - UAV
• 5 Kills - Counter-UAV
• 5 Kills - Ballistic Vests
• 5 Kills - Airdrop Trap
• 8 Kills - SAM Turret
• 10 Kills - Recon Drone
• 12 Kills - Advanced UAV
• 12 Kills - Remote Turret
• 14 Kills - Stealth Bomber
• 18 Kills - EMP
• 18 Kills - Juggernaut Recon
• 18 Kills - Escort Airdrop.