While Apple has released iOS 4.0.2 for iPhone 4, 3GS and 3G, the important thing is that they haven't updated the baseband. What this means is that 05.13.04 baseband which accompanies iOS 4.0.2 is still unlockable with ultrasn0w provided that you manage to jailbreak your iOS device. At the moment, only iPhone 3G and iPod touch 2G (Non-MC model) can be jailbroken on this latest firmware using the latest version of Redsn0w. So technically, you can only unlock iPhone 3G on iOS 4.0.2.
