Enabling Cheat Mode
Enable cheat mode in the developer console by navigating to the installation folder for the game. Open the file called "civ4config" in notepad. Find the line with the text "CheatCode = 0" and change it to "CheatCode = chipotle" and then save the file. Open the developer console in the game by pressing the "~" key located at the top left of your keyboard.
Changing the Geography
You can change geographical features to your liking using cheat mode commands in the developer console. Toggle water on or off by typing "Graphics.toggleWater" into the console and pressing "Enter." You can replot many of the geographical features, such as goodies, bonuses, features and rivers, by typing "Map.generate[thing]" and pressing "Enter." For this command, replace "[thing]" with the name of one of the four things you'd like to replot without the square brackets. For example, type "Map.generateGoodies" and press "Enter" to replot the goodies. You can replace or erase replotted commands by typing in either "Map.eraseGameElements" or "Map.replaceGameElements" and pressing "Enter."
Player and City Cheats
From within the developer console you can enter a number of cheat codes that will benefit your faction and cities. Set your gold, or the gold of other players, by typing "Player.changeGold [player number], [gold]"; [player number] sets who gets the gold and "[gold] is the amount you wish the gold changed to. Because you are player 0, to change your own gold, you would type "Player.changeGold 0, 10000" and press "Enter" to give yourself 10000 gold. Access the city editor by highlighting the city you wish to edit, pressing and holding the "Ctrl" and "Alt" keys and clicking the left mouse button.
Debug Commands
Enter the developer console by pressing the "~" key. Type in "Game.toggleDebugMode" and press "Enter." From here you can perform a number of cheats that can help your game. Increase your gold by 1,000 by holding the "Ctrl" key and pressing "4." Level up a unit by highlighting it and pressing the "+" key. Instantly complete city production orders by highlighting a city pressing the "+" key. Increase or decrease a unit's strength by highlighting it, holding the "Shift" key and pressing the "[" key to decrease the strength and "]" key to increase the strength of the highlighted unit.