iOS 7 has landed and with no surprise Apple’s servers are buckling under what must be an enormous strain right now.
Unable to Verify Update
iOS 7 failed verification because you are no longer connected to the internet.
If you are unlucky enough to be getting this error message the only thing you can do right now is just sit and wait whilst downloads are done and the strain eases off the Apple servers. If you are really desperate to update then try again in the wee small hours of the morning.