Start the game using the command line parameter. To do this, right click a shortcut on your desktop and edit the properties:
C:\Call of Duty\CoDSP.exe" +set thereisacow 1337 +set developer 1 +set sv_cheats 1 +set monkeytoy 0
Now, during the gameplay, press ~ and enter the codes in the console window:
God mode: God
Weapons, items and ammo: give all
Enemies don't target you: notarget
No clipping mode: noclip
Max out ammo: give ammo
Fly mode: ufo
Suicide: kill
Teleportation: jumptonode
Turns off/on fog: r_fog 0/1