@dlowan,
They messed up the update with forcing this security increased procedure on the members who are updating OS .
If you go to Apple store, they'll fix it in 3 minutes. They blasted an explanation over the last few days in all of the media outlets about this 'glitch'. This has been posted in a lot of place on the Internet:
http://news.sky.com/story/1217187/iphone-and-ipad-users-hit-by-security-glitch
I had to go to Apple store and get my IPhone ' fixed' You have to log into your Apple account (and remember your username and password, etc) . Once you've logged in, run the ' Where's my Iphone' application. which is where you're forced to go to by the update.
That's where they messed up with this update of the iOS due to their choice of forcing tighter security.