With Apple's revamped Game Center that has been brought to iOS 7, third-party developers may want to integrate a controller for a bit more functionality. To sweeten the deal, Apple further announced an API for third-party MFi game controllers, during WWDC last Monday.
Leave it to Logitech, one of the more premiere gaming accessory makers, to develop a game controller just for the iPhone. A leaked image of the controller has been obtained by Kotaku and indicates compatibility with the iPhone 5 (and perhaps iPhone 5S later this year). You can find four buttons to the right and joystick to the left. There's a Lightning port as well, where all the connectivity will inevitably go down.
According to Kotaku, we won't see an official game controller out of Apple, though that probably won't stop third parties from taking in influence from the Cupertino-based company. Apart from Logitech, it would make sense for others to jump into the game as well, including Mad Catz which has promised a slew of accessories for mobile devices this year. What Logitech has developed looks pretty solid.
There's no word on a release date or pricing for the leaked Logitech controller. Given the autumn release for iOS 7, that time period makes the most sense.