So how do you go about making a skin? I already have The Gimp, which i use for editing pictures, but i dont know how to make a skin. Mabey a more experienced person can help me?

Best way to go about would be using these:
http://www.lfs-gear.com/kitz.html

and these tutorials will get you started on the basics:
http://www.lfs-gear.com/TUTORIALS/Tutorials.html

After that it's just up to your imagination and a little practice