The classic text is Nielsen and Chuang's "Quantum Computation and Quantum Information" [0]. Whatever else you choose to supplement this book with, it is worth having in your library.
Nielsen and Chuang has the clearest exposition of quantum mechanics I've seen anywhere. Last year I was trying to learn quantum mechanics, not necessarily quantum computation, just out of a general interest in theoretical physics. I started with physics textbooks (Griffiths and Shankar) but it only really "clicked" for me when I read the first few chapters of Nielsen and Chuang.
Nielsen and Chuang has the clearest exposition of quantum mechanics I've seen anywhere. Last year I was trying to learn quantum mechanics, not necessarily quantum computation, just out of a general interest in theoretical physics. I started with physics textbooks (Griffiths and Shankar) but it only really "clicked" for me when I read the first few chapters of Nielsen and Chuang.