There is a way to change your skin without buying the game (this is legal)

1. download a skin

2. goto your start menu type %appdata%

3. goto roaming

4. goto your minecraft folder

5. goto bin

6. open you minecraft.jar with WinRAR of 7zip

7. find the folder mob in your minecraft.jar

8.find char.png in mob

9. delete char.png

10. move your skin in mob and rename it char.png

11. open minecraft

12 Done and enjoy!!!

(Hint this willl only work in singleplayer)

yes this will work with minecraft 1.5.2 and above

This is how to do it on windows 7 64-bit (this will work on windows 7 32-bit

Thank you