Various cheats
     Start  the game with the command-line parameter 
"+set thereisacow 1337  +set  developer 1 +set sv_cheats 1 
+set monkeytoy 0" 
to activate the  cheat codes. While playing, press ` to bring up 
the console, then type any of the following codes:

Example: 
"C:\Call of Duty\CoDUOSP.exe" +set thereisacow 1337 +set developer 1 
+set sv_cheats 1 +set monkeytoy 0

Cheat code:             Effect:
god                     God Mode
noclip                  No Clipping Mode
give all                All Weapons, Ammo, Items
give ammo               Full Ammo
notarget                Enemies Ignore You