Press control-shift-c and the cheat box will pop up. Type in, without quotations, the following: "boolProp testingCheatsEnabled true". It is not case sensitive, I just put caps in there to make it easier to read.
It is best to enter that code in the neighborhood screen, but if you didn't, just save, exit and re-enter the house you were playing. Now the cheat will be in effect. You can control-click any want or fear you may have and it will register--you'll get your aspiration points (both for rewards and the meter) and another want or fear will replace it.
You can click and drag any selectable sim's motives anywhere you wish them. This also works for relationships, though keep in mind that it only affects the sim you selected and won't make friends for you. The click-and-drag also works for personalities and skill points, though maxing the skill this way, like anything else you do by this cheat, will not give you a memory.
You can also get a lot more options by shift-clicking the mailbox or shift-clicking your Sim (note that if you use the Tombstone of Life and Death to make friends, you won't get the friend icons unless you then interact with them), but since there are so many of them, I recommend this online resource:
http://groups.msn.com/TheSims2Database/yourwebpage.msnwI've tried many of them on my Mac OS X Sims game and all the ones I've tried work.
To turn it off, pull up the cheat window again and type in, without quotations, "boolProp testingCheatsEnabled false" (again not case sensitive), save, and re-enter the house.