The iPhone has been on the market for nearly four years now. More than 350 000 apps are currently shipping on the App Store by more than 85 000 different developers. We can start to see emerging user interface design patterns. I made a two discoveries in that regard. The first one is pttrns, a web site about showing design examples categorized by application functionality like login screens, list views, user profiles, etc. The second discovery is Mobile UI Patterns by the lead designer at Foursquare, Mari Sheibley. So, if you are designing iOS applications and are looking for inspiration, this is the place to go.