I've heard of Google Print, and it sounded like a neat idea, but I haven't really looked into it. Kevin Cawley has offered a post that helped me jump in and see the real value of this resource.
From the Google blog...
Imagine sitting at your computer and, in less than a second, searching the full text of every book ever written. Imagine an historian being able to instantly find every book that mentions the Battle of Algiers. Imagine a high school student in Bangladesh discovering an out-of-print author held only in a library in Ann Arbor. Imagine one giant electronic card catalog that makes all the world's books discoverable with just a few keystrokes by anyone, anywhere, anytime.