Decalgirl has posted up some iPhone skins. I purchased a Wii skin from them a while back and it's looking great still after many months of use.
If your wondering how they got the screen to look like that, each skin comes with a wallpaper that you put on your iphone to complete the style across the entire front and back of the phone. For only $6.99 it seems like a pretty good deal. I wish decalgirl would let you submit (or even sell) your own designs. Then we could have some fun with this.
I will order one to try it out, and post some pics letting you know if it's worth it or not. Stay tuned.
Check out all of these iPhone Skins