NOTE: These cheats are for the demo version of Call of Duty 2. Re-submitting these cheats for the full version of the game pretty much marks you for death by most COD2 players unless the cheat is personally verified by an IGN or Gamespy editor to work on the retail (final) version.

Enable the console from the game's in-game options. Hit the tilde key (next to the numeric 1 key on the number row) to drop the dev-console. Input seta thereisacow "1337" and then press ENTER. Input spdevmap eldaba. and then press ENTER. This will start the demo with cheats enabled. When playing, drop down the dev-console and enter the following codes and hit ENTER to activate or toggle them.

give all ... Attain two random weapons.
give ammo ... Portable ammunition dump (just add water).
god ... Player invulnerablity.
noclip ... Ghost/clipping mode toggle.
notarget ... Enemy AI toggle.
jump_height ... Adjusts gravity. Value 039 is default.
timescale ... Adjusts passage of time. Value 1.00 is default.