[Holden]

I have a Cybook 3 generation and lots of ebooks.
I live in Italy and a friend of mine is going to New York. I was thinking of buying a Kindle 3, as the price is tempting.
Somebody told me that you will be asked some personal information when you buy a kindle, but this is not clear for me, What is it for? for downloading from Amazon?
Second question: Kindle and Cybook use the same files? mobi, isn't it?
Third Question: What about the screen resolution? Is it better to read than my Cybook?
Fourth question: Can you buy it at Barnes and Nobles? If not, which is the best place where I can send my friend to buy it?

(I might have found all the answer in the other threads, but there are so many that I got lost