I'm going to post a link that will take you to a really great sims 2 site. You don't have to register to be able to read the cheats and other things on the site and I've been using that site for years and have never gotten a virus from it.
http://www.snootysims.com/cheatsindex.php?id=cheats
After you look at the cheats, there are more listed at the top under the word boolprop. Also, on the side you can click on other things to find out things about the careers, the career rewards, the aspiration rewards, etc.
Also, I have been using a painting that I found way back when I only had the original base game called The Sims 2 that does a lot of things. It comes in a zipped file though so you have to extract it from the zipped file and then you need to put it here:
XP -- My Documents/ EA Games/ The Sims 2/ Downloads
Vista -- C:\User\UserName\Documents\EA Games\The Sims 2\Downloads.
I'm going to paste a link to get the picture but when you click on the link you then need to look to the left and click on Merola's Sims 2. Then count down to the eigth small picture and click on that. Now you will see a bigger picture with the words Multi Painting in red underneath the picture. Don't worry about the fact that it looks like it's in a foreign language as it's not -- in my game it's in English and the same with my friends game.
Anyway, this painting will do LOTS of things, including raising their motives, changing their interests, jobs, personality, etc. If you get this painting, you really won't need to use the cheats much, if at all.
Here's the link for the painting:
http://www.simchaotics.com/
Also, I have used this painting even though I have added all the stuff packs and expansion packs up to Celebrations and it has always worked and never caused me any problems. I have a friend who has different games than I do and she uses it without problems also.