To enable cheat mode, press CTRL+SHIFT+C. Thus you will bring up the console window where you can enter one of the codes you see below:
the list of the cheat codes: help
shows information about any cheat: help [command]
exit cheat mode: exit
expand console window: expand
get 1,000 Simoleons: Kaching
get 50,000 Simoleons: motherlode
twins: twinzr2cute
remove all Sims: deleteAllCharacters
terrain types: TerrainType [desert or temperate]
place objects anywhere: moveObjects [on or off]
larger or smaller Sims: StretchSkeleton [number]
facial DNA blending in "Create a Sim": faceBlendLimits [on or off]
prevent Sims from aging: aging [on or off]
get automatic game updates: autoPatch [on or off]
toggle slow motion: slowMotion [0-8]
no censor: intprop censorgridsize 0 (8 - normal)