You can create your own skin for your device and upload your own images to be used in the creation of your design.
I figured I would give it a go and this was my result:
Before images on the left, After images on the right.
Front
Back
I am a huge fan of Fight Club so I used images from the movie to make my design. The bottom picture on the front of the phone was from the signature that I made:
The flash makes it look worse than it actually does, I straightened out the stickers on the front soon after taking the picture.
The material they use is along the lines of Duct-Tape and it allows you to remove the sticker and reapply it plenty of times in case you screw up. So it's not an all or nothing type of deal.
Also on the front of my phone I applied an Invisible Shield from Zagg, seen here, to protect the screen from scratches and stuff. Apparently it's stuff they use in the Military and it's a nice addition, easy to apply.
The gelaskins impressed me greatly and I am considering making a design for my 360 controller.
You can pretty much create a design for any device on that site.
So if there are any of you out there that doesn't want to spend $400 for the Star Wars Xbox 360 Slim than you can just create it there for about $30 bucks.