Yes, I'll get my replacement tomorrow, as a matter of fact TNT (Apple's EU courier) called me today: I've scheduled to pick it up on monday, 23.
To register your product just plug your nano in and iTunes should come up, you will have to fill a form to register it. It's that easy.
If you desire you can register your product via web as well, just go to
https://register.apple.com/
Hope this can help.