Note: This involves editing a game file. Always make a backup before changing.
Open your Civilization config file (\Documents and Settings\USERNAME\My Games\Sid Meier's Civilization 4\CivilizationIV.ini) with Notepad and change the following line:
; Move along
CheatCode = 0
; Move along
CheatCode = chipotle
Once cheats have been enabled, while playing open up the console using "~" (tilde) then type "help" for a list of cheat commands.
Cheat Code Example: Type Player.setGold 0 1000000 to add more gold.
You can also type Console.CreateDocumentation CommandList.txt to create a list of cheat commands in a text file which can be found in the game directory.
After applying "CheatCode = chipotle" in the configuration file, you can enter from console windows (open by using ~) the command "game.toggledebugmode" (without quotemarks).
That will enable the cheat-dialog by pressing [SHIFT]+T. From this dialog you can alter amount of Gold and level of technology for players in the game.
Download: Trainer 1.7.4
One Turn Creation of Units, Buildings and Research, Unlimited Movement of Units. Made exclusively for Cheat Happens. WRITTEN FOR THE PATCHED 1.7.4 VERSION OF THE GAME. ALSO INCLUDES A TRAINER FOR BEYOND THE SWORD EXPANSION. May not work with all versions. Read the included readme file with Notepad for important instructions on using the trainer.(Downloads are on an external site and open in a new window)
Includes a pre-modified config file to activate cheats and a complete list of cheats that can be used in the game. Read included .nfo file for instructions.(Downloads are on an external site and open in a new window)