Edit: After half day, my wife’s Mac started having the same problem. I have then applied the solution that I found in the Apple
Apple Release iOS 6 To The Public
You can update by either going to iTunes and selecting “Check for updates” or over the air by going to Settings > General > Software update. Do not worry if you do not see it yet just give it a few minutes to reach the masses.
iOS 6 adds over 200 new features including Facebook integration , Siri improvements , Apples own maps and also Passbook.