SimPE
SimPE is a community-based software program used specifically for editing different aspects of "The Sims 2." This software will not be compatible with any other "Sims" game. This software is essential for creating new Sims, changing hair color, skin tone and clothes. Within the program is an item called "Sim Surgery," used to accomplish these goals. Although the process can be tricky at first, it becomes easier as you perform surgery more often.
Sims Surgery
After installing the SimPE software on your computer, you will have the option to clone your Sim, or make an exact copy of your Sim that you want to change in Sim Surgery. Open SimPE, go to "Sims Surgery" and go to "Body Shop." This will open the program used to change physical characteristics, such as skin tone. After applying the skin tone changes, copy this changed Sim and paste this copy into the game.
Compatible Downloads
The "Sims" website contains a region for downloads that community gamers can contribute to and download from. These downloads are often expansion downloads, which can add clothing options, hairstyles and skin tones. Some downloads will feature skin tone selection tools, which can help change the skin tone of any desired skin. It isn't uncommon for these same downloads to include options to change hair color and other physical characteristics, such as weight and eye color.
Starting a New Game
If the aforementioned options become too challenging for any reason, the simplest thing you can do is to create a new game. This will help you to create brand new Sims with the skin tone you desire. If you want your new Sims to live in the same house, you can simply evict the other family or bulldoze down that house and rebuild it. Although this will negate any hard work you put into your previous Sims, it will still help to accomplish your goal.