Amazon.com just posted my five star review of Google Hacking for Penetration Testers. In short, this book rocks. From the review:
"'Google Hacking for Penetration Testers' (GHFPT) should be a wake-up call for organizations that consider 'information leakage' a theoretical problem. 'Information leakage' refers to the unintentional disclosure of sensitive information to public forums, like the Web. Security staff can use the tools and techniques outlined in Johnny Long's GHFPT to assess the degree of information leakage affecting their organizations. They can then propose, implement, and test remedies. When Google says they are clean, they can be reasonably assured they are."
I recommend visiting the author's site at johnny.ihackstuff.com to download his Shmoocon slides. They are a good overview of the book.