I ordered Skins for beautification of my iPhone from www.gelaskins.com
They aren't cheap but not expensive either. I've got them on my phone for a month now and I'm not dissapointed. Putting it onto the iphone without any bubbles in the corners is possible, but very very little wrinkles always remain on the 3g (have a look at the pictures).
The screen protector is great as well but if you want a shiny surface you have to replace it every month, because they get easily scratched. I like the additional protection for my display because I'm a bit paranoid regarding the glass of the iphone ;)
Take your time for putting the skins onto your phone, align it to the left or right side and you'll enjoy gelaskins.