To unlock the cheat, you must pause your game, and simultaneously press L1,R1,L2, and R2. Then, a notice will pop up and tell you to save an extra game because once you use the cheats, your challenges are stopped. If you persist, it will tell you that you can find the llama in the miscellaneous decor section in buy/build mode. Place it on your house lot and click on it to use the cheats. A few of the cheats that you can use are fill karma, unlock challenge rewards, get lifetime savings, motherlode(50,000 $), and there are some more. I hope this helped.
Added by: Guest Oct 31st 2010, ID#3235