These links should help you out quite a bit

Halo 3

• Halo 3 Armor
• Halo 3 Cheats
• Halo 3 Medals
• Halo 3 Skulls

Call of Duty 4

• Call of Duty 4 Challenges
• Call of Duty 4 Game Modes
• Call of Duty 4 Inventory Items
• Call of Duty 4 Multiplayer Ranks
• Call of Duty 4 Perks
• Call of Duty 4 Trailer
• Call of Duty 4 Weapons