Back a couple of weeks ago I had the privilege of participating in a Pain of the Week webcast with Kevin E. Kline on SQL injection. The webinar archive is now online if you didn't get a chance to view it live:
One of the things I talked about was how attackers will use search engines to try and locate targets. This is typically known as Google Hacking and the guy who I most know for this is Johnny Long. He has a Google Hacking Database online.