iPhone registration...

I was wondering how to get back to the iPhone registration screen... I don't suppose it's very important, however, I would like to know if you can get back... For some reason it's annoying me that I can't find how to get back! I am talking about the first screen you see on iTunes when you connect it to iTunes for the first time and it says something like, 'Set Up your iPhone' and it lets you name it and register it to your Apple Account. I know how to rename my iPhone, but I want to register it to my Apple Account. Any ideas? Thanks!