Although iOS 6 will support older devices (up to the 3GS), these older devices won’t get some of the newest features. One of those features is the new ‘Flyover’ 3D in the new iOS 6 maps. Luckily, as usual, you might get the feature after all thanks to a jailbreak hack.
If you cannot wait, the user has also posted instructions for doing so on your own iPhone 4, though beware, this is not for beginners.Although he was able to enable 3D maps and Flyover, he has been unable to get turn-by-turn directions to work on his iPhone 4.
Based on the videos performance doesn’t look too bad, although keep in mind iOS 6 is months away and everything is subject to change. I wouldn’t hold my breath for Apple to officially add these features to the iPhone 4.