Enable Cheat Console

For XP Users:
Go to C:\Documents and Settings\[USERNAME]\My Documents\My Games\Gears of War
for Windows\WarGame\Config

Find the "WarInput.ini" file and open it with Notepad

For VISTA Users:
Go to [USERNAME]\Documents\My Games\Gears of War for Windows\Wargame\Config

Find the "WarInput.ini" file and open it with Notepad

Both Users:
Add or change the following lines:

[Engine.Console]
ConsoleKey=Tilde
TypeKey=Tilde
MaxScrollbackSize=1024
HistoryBot=-1
bEnableUI=True

Start your game and press Tilde (~) to bring up the console, then type in the
following codes to get the results:

Also note if you want to easily activate multiple cheats at once just create a
Notepad file in your Gears of War\Binaries folder and name it whatever you want like "cheats.txt" save all the cheat command lines you want inside the file.

Start the game and open the cheat console to type:

exec cheats.txt