Here are some simple single player tips, tricks, and cheats for the Call of Duty 4 single player mode on PC.

Start up Call of Duty 4 single player, go into your options, and make sure that the console is enabled.

Press your ~ (tilde) key anytime you want to enter these codes in  you can keep entering them.
First off, type seta thereisacow "1337", this enables most of the cheats.

In order to pick a level, use spdevmap mapname

Here are some handy console commands that may help you through the game:

ufo  you can fly through walls to get places  be careful, this can mess things up a little, and you may get stuck
give  gives you an item. If you type give all, you will get all weapons
god  god mode!
demigod  god mode, but some things still happen like screen shaking and such
notarget  you will be invisible to enemies
give ammo  instant ammo
jump_height  allows you to change the physics in the game  like moon shoes
timescale  lets you play with time  fast or slow
cg_LaserForceOn  laser sight, baby!

To insert the following codes, enable the console from the in-game options. Press ~ and type in seta thereisacow 1337?, pressing Enter thereafter. From here, type spdevmap bog_a and press Enter again. Then, you can insert the following cheats. this is how you do it

* cg_drawgun  Drop your gun
* cg_fov  Zoom with any gun
* cg_LaserForceOn 1  Laser site with any gun
* demigod  God Mode (with shaking screen)
* give (item)  Acquire any item
* give all  Get any weapon
* give ammo  Full ammo
* god  God Mode (without screen shaking)
* jump_height #  Adjust gravity (39 is default)
* noclip  No Clipping
* notarget  Dumb AI
* r_fullbright  Brighter features
* timescale #  Adjust the time (1.00 is default)
* ufo  No Clipping (II)

Map Names:
ac130,aftermath,airlift,airplane,ambush,armada,blackout,bog_a,bog_b
,cargoship,coup,hunted,icbm,jeepride,killhouse,launchfacilty_a,
launchfacilty_b,scoutsniper,sniperescape,village_assault,village_defend