To open the cheat menu, press Ctrl+Shift+C at the same time.

Codes

kaching - gives you 1000 simoleons
motherlode - gives you 50,000 simoleons
moveObjects (on/off) - allows you to move objects you can't ordinarily move (note: you cannot delete dishes, trash, or wastes like you can in The Sims. You can still delete people, but they will not ever reappear.)
aging (on/off) - turns on or off aging. works on entire household but not on whole neighborhood.
help- all - lists all cheats
exit - closes cheat console

Credit to: Nimby90@aol.com

Other Parameters :
Add these to the shortcut's parameters for other helpful things. Some have code counterparts. Get This By Doing This: Fullscreen Mode -f. Start with desired resolution (in pixels). -r[width]x[height]
Disables sound -nosound
Windowed Mode -w

Misc. Codes Press CTRL + SHIFT + C to access the cheat window, then enter the following: Get This By Doing This :
increases game performance but lowers graphics vsync (on/off) lets you know if theres a patch: autopatch (on/off)
moves objects and deletes you couldnt before: moveobjects (on/off)
get 1000 cash: kaching
list cheats: help -all
closes cheat window: exit
expands or contracts cheat window: expand
makes your sims larger or smaller: StretchSkeleton
turn off aging: aging off
turn on aging: aging on
50,000 simoleans: motherlode
Turn off facial bounding limitations. It prevents the normal corrections the game will make for two parents with very different facial structures: faceBlendLimits (on/off)
You can invite more people to your parties: intProp maxNumOfVisitingSims 8
You can place objects outside the grid: boolProp snapObjectsToGrid true/false

Neighborhood Only Cheats:
Bring up cheat window by pressing Ctrl + Alt + C
At neighborhood view only, removes every Sim from the neighborhood: deleteAllCharacters
Only for use in neighborhood view, toggles between the two terrain types: TerrainType (desert/temperate)

More Codes
Press Ctrl + Shift + C to access the console. S
ome cheats require you enter the Postprocessing cheat.
Make you set the game speed: (# = 0 to 8, 0 is normal) slowMotion #
Turns Postprocessing on: boolProp enablePostProcessing true
Turns Postprocessing off: boolProp enablePostProcessing false
Sitcom flashback blur effect: (# = 0.0 to 1.0) (require postprocessing on) bloom rgb #
Blurry bits at the edge of the screen: (# = 0.0 to 1.0) (require postprocessing on) vignette # # #
Makes the screen grainy: (# = 0.0 to 1.0) (require postprocessing on) filmGrain #
Adds a letterbox effect to the view: (# = 0.0 to 0.4) (require postprocessing on) letterBox #

Credit for THIS poo-load of codes: aaron884@msn.com