Google has introduces a book search system called it Google Print. The service provides book information and excerpts on the Web.

Google Print FAQ (http://print.google.com/print/faq.html)

It seems to be still very early beta; to have a look what books were indexed so far, click here (http://www.google.com/search?q=site%3Aprint.google.com+inurl%3Aprint)