Just ahead of the iPhone 4S launch comes the latest operating system for Apple's mobile device ecosystem, iOS 5. A software update for iPhone 3GS, iPhone 4 and iPhone 4S, together with support for both iPads and recent iPods, iOS 5 will add more than 200 new features including the highly-anticipated iMessage platform.

Some of the new features include: the ability to sync your device without having to be hooked up to a computer; an entirely new Notification Centre which offers an innovative way to easily view and manage notifications in one place without interruption; and iMessage, a whole new messaging system that lets you send text messages and photos between all iOS 5 users, much in the same vein as BlackBerry Messenger.

Other features include Newsstand, a new platform for purchasing and organising newspaper and magazine subscriptions and, of course, iCloud, which will let users store and access their music, photos and files wirelessly across all of its Apple devices.

Apple has already launched iTunes 10.5 and has begun allowing users to sign up for its new iCloud service in preparation for the release of iOS 5.

Apple announced Monday that the iPhone 4S received more than a million pre-orders in the first 24 hours of it being made available.