With the release of iOS 6 later this fall, users of the iPhone 3GS or later, iPad 2 or later and iPod touch (4th generation) will receive the free update. Previous generation models are not supported. Some devices will not receive all of the features of iOS 6. To help guide you through the maze of features and supported devices, we present you with this handy iOS 6 compatibility matrix. iOS 6 is currently in beta, so it is entirely possible that a final release will offer increased support for older models. We'll update this regularly, should we hear any changes.
iOS 6 Features and Compatibility Matrix is an article from everythingiCafe.
Via: everythingiCafe