Well, this is the one I learned from:
http://www.modthesims2.com/showthread.php?t=102356
The one thing I'd warn you about is to click the pushpin in the Object Workshop window so it doesn't "sprong" closed on you inadvertently.
A second warning: Register a user name at the SimPE site and use SimPE to log in with it. Then your username is added to the internal file names. Very important if you should ever need to prove something is "yours."