Verified answer

No, you cannot. A player can only change their character's skin if they purchased Minecraft. Get Minecraft gift codes here to activate your premium account and then you can change your skin or create a skin to personalize your player model.

Go to the official website, go to your profile, and then theres a skin change option.

You only can if you have bought yourself a Premium account.

If you have one, click on the "Profile" button and follow the instructions.

http://www.youtube.com/watch?v=C3wslH-22Fk