For starters, those looking forward to Siri will be disappointed to learn that it will only be available for the new iPad and the iPhone 4S, as is the ability to make FaceTime calls over cellular data. As far as the new Maps app is concerned, it seems that only iPhone 4S, iPad 2 and the new iPad will be getting a taste of that. Other features such as the VIP mailbox, offline reading for Safari and the Shared Photo Stream will arrive on devices like the iPhone 4 and the iPad 2 (and presumably devices newer than them).
Basically it seems that even though the iPhone 3GS will be getting the iOS 6 update, the major iOS 6 features and functions will not be enabled for the device. Granted it is 3 years old so we guess it has had a pretty good run, right? iPhone 3GS users are you bummed at this, or were you planning on upgrading anyway? In the meantime check out the table below compiled courtesy of Engadget: