Please check out MASTERSIMMER'S awesome tutorial "HOW TO MAKE GREAT MOVIES" !! This tutorial is in .pdf format (Adobe Acrobat Reader). Click here to become a master at making movies !! Thank you, MASTERSIMMER, for this awesome tutorial !! Text (.txt) version here.

Linda's Sims 2 Tutorials are THE way to go if you want to learn how to recolor objects with SimPE (step by step with pictures and easy to understand), how to make clothes for your Sims, how to make basements, how to make specially shaped pools and MUCH more. One of the best sites with Sims 2 Tutorials that I could find. Plus, Buntah has object downloads and clothes downloads. This site is a MUST SEE.

How to successfully edit an existing Sim (either made in the game, not BodyShop, or born into an existing Sim Family) / tutorial from here

You'll need SimPE to do this, it's a free program that you can download here.

I successfully copied out existing sims to bodyshop.

As I previous posted, I have succeeded in replacing existing sims character file with other (new or existing) sims character file to change sim's face and name.
If your intension is just changing existing sim's face while preserving house, career, skill and friends/family relationship of existing sim, that was enough.

But I could not convert existing sim character file to "pre-made" sim package file which can be uploaded or be edited in Bodyshop, until now.

Now I can do that. At least, hardest part is solved.

This is how I did it:

1. Run SimPE. Open character file of sim you try to copy out
in "...\Neighborhoods\N00X\Characters" folder.

2. Extract "Data File" (type=0xCCCEF852) to file. Quit SimPE

3. Run Bodyshop. Create a new sim with same sex and age group with existing sim.

4. Adjust skin tone, eye color, hair style (all genetic except face features) to look similar to existing sim. Optionally, Adjust make-ups and clothings so that it looks like existing sim. No need to adjust face features.
Save the sim. Quit Body shop.

5. Run simPE. Open newly created pre-made sim package file in "...\SavedSims".

6. Replace "Data file" of new sim with "Data File" extracted from the existing sim. Save package file. Quit SimPE.

7. Run Bodyshop. You can see modified "pre-made" sim.
Adjust make-up to let new sim look same as existing sim. Save it.

Now you have "pre-made" sim which looks same as existing sim that was created in in-game "CAS" or baby born in game.

Point is that importing "Data File" from character file of existing sims which stores face feature of the sim.
Now, we can copy face feature of existing sim. This was hardest part.
It is easy job to let sim have same skin tone, hair-style, eye color, make up and clothings.

Now, make modification to your new sim in Bodyshop. Save it.

Then replace existing sim's face with newly modified sim
as I explained in previous posting at "Charter modification with SimPE" thread which you can find here.

SimMasterRalph has the BEST tutorials about how to make a split entry home, a spiral stairs tutorial, an underground basement garage tutorial, a tutorial about split stairs and a tutorial about a roof covered porch. Go check his tutorials out here.

MikeInside has the BEST tutorials about how to build basements, modular stairs, custom roofs, circular stairways, sloped floortiles, bridges, custom objects with the "moveobjects on" cheat, advanced internal stairs, waterslides, split level homes and custom pool ideas. This guy is a MASTER at building houses and he has a lot of his awesome houses for download on his site too. This site is a definite bookmark !! Please go here.