The book that I suggested before was this one:
Microsoft® XNA Game Studio Creators Guide by Stephen Cawood and Pat McGee
But now I bought this other book that can be even more easy to follow for begginers. The guy that wrote the book explains everything in a simple way, allowing everyone to understand it, even people with no knoledge of game programming like myself.
Microsoft(R) XNA(TM) Unleashed: Graphics and Game Programming for Xbox 360 and Windows (Unleashed)
So, these three books are a must have for all people learning XNA.