The following are known Action Replay Codes for Call of Duty 4: Modern Warfare on Nintendo DS (NDS).

Game ID: YCOE-0575F79E

Infinite Health
020180f0 e0410000

AMMO CODES:

Infinte Ammo
020961e4 e1a00000

Fire for Max Ammo
020961e4 e3a00064

Fire Weapon To Gain Ammo
020961e4 e2800001

GRENADE CODES:

Infinite Grenades
020965b4 e1a00000

Throw Grenade for Max Grenades
020965b4 e3a00064

Throw Grenade to Gain Grenades
020965b4 e2800001