Finally, we have learnt that Apple will be releasing iOS 5 for customers in Fall of 2012. However, developers will be getting an iOS 5 seed today, for the SDK.
iOS 5 will support iPhone 3GS, iPhone 4, the original iPad, the iPad 2 and the iPod touch 3G and 4G, as well as the next generation Apple devices. Future updates for iOS 5 will be OTA, in which only the changes will be downloaded. Hence it will be really easy to update firmware on devices running iOS 5.
Later today, developers will be getting an iOS 5 seed for the SDK.