Already downloaded ios 5 from itunes. Trying to make me download it again?

I spent most the day downloading ios 5 for my iphone 4. I chose the download only option. When it was done I plug in my phone. Now what? If I choose update, it downloads ios 5 all over again. If I choose restore it does the same thing.

Please help! Don't want to spend another two hours waiting to download this!