Two days ahead of the iPhone 5 launch, owners of older iPhones and iPads will be able to update to iOS 6 from today. The update is available for the iPhone 4S, iPhone 4 and iPhone 3GS via an over-the-air update or through iTunes later this evening (6-7pm GMT).
iOS 6 is said to have over 200 new features, the most notable being Facebook integration, panorama camera mode (for iPhone 5 and iPhone 4S only), an improved Siri, Passbook, FaceTime over 3G, and a new Maps app. Maps now offers turn-by-turn navigation but UK users will not be able to use the 3D flyover mode, which is restricted to certain US cities.
The iPhone 5 goes on sale on Friday and due to the high volume of pre-orders there may be a shortage of stock with some retailers for the next week or two.