If you are looking for superb iPhoneography, you need look no further than Matt Burrows over on Flickr. Matt uses a number of different apps to make his shots such as Cross Process, ShakeItPhoto and Hipstamatic. His compositions are often very simple, yet blindly brilliant at the same time, featuring graphic shapes and vivid colors.
More often than not, he leaves me scratching my head how he got such a brilliant shot with a mere camera phone. Goes to prove that an artist can make art with the simplest of tools and need not have a flashy multi thousand dollar setup. Still, makes me wonder what would happen if we stuck a Canon 5D2 or Nikon D700 in his hands!