There has been much debate about the digitalisation of books by Google. Frankly, much of the debate has been alarmist and a little counter productive. Google Books is extremely useful and the quirks in the system largely manageable by simple double-checking. There are obvious flaws, but in the absence of anyone else stepping up to take on such an enormous task, excusable (although, we should keep an eye on them).
One of my colleagues, Patrick Spedding, blogged very eloquently about some of the issues here.