Well I think you can through your nook account if your nook is destroyed. Or do you mean let a friend borrow a book the answer is yes for most nook books.
no
The NookColor defeats the purpose of an e-reader. The Nook is supposed to help you with your eyes, by not looking at the bright screens.
NookColor is an advanced and better version of the Nook. The NookColor includes Pandora Radio, reading a book aloud, color touch screen, and more.
nope the nook is much smaller than the nook color! dah!