Rockstar
At first glance, the iPhone wallpapers on this site looks like images from a really cool gallery, which is exactly what they are. All of these are designs from illustrators and designers; Poolga is a resource of art made especially for your iPhone.

They offer a super stylish selection of iPhone and iPod Touch wallpapers from a global selection of designers and illustrators. Poolga is a site made by creative people who want to give their phones some love, and share them online.