I usually go on stardoll.com. You can dress up some celebrities including Miley Cyrus, Dylan & Cole Sprouse, Rihanna and Zac Efron. This Might sound to you like it is for girls only, but a few of boys joined stardoll.

If you make an account on stardoll you pick a username and password. Then you make your Me Doll, where you make yourself as a cartoon. You first star with your own suite. You can earn starpoints by saving dolls in your album to win prizes for the suite. Many members of Stardoll pay to be a superstar. You can have more privileges this way. I think being a normal member of stardoll is enough.