On bebo it gives you all the information you need.
1) When signed in to bebo click on profile to view your own profile.
2) Underneath your display picture click on 'Change Skins'.
3) At the top click on 'Roll Your Own'.
4) Then underneath the subheading 'Sounds like a lark, how do I get started?' Click on 'Check out the tutorial to get a feel of what it takes to build skins.'
There it shows you simple steps to make a skin on photoshop.