I want to create a hackbot for ethical hacking

Dear PHP Webmaster, I want to create a pretty simple PHP robot, but I need your help because I can't seem to get it right. I discovered yesterday that if you use Google to type in "inurl:index.php?id=", then you can find pages that might be vulnerable to SQL Injection. If you just type in a single quote (') after the URL, then it is vulnerable if you get an SQL error, but it is not vulnerable if the page does not change or if you get an Error 404. I want to have a PHP robot that will search for "inurl:index.php?id=", follow all the links on Google, and tell me if the sites are vulnerable. I don't want the robot to steal the passwords or anything, I just want the robot to tell me if the sites are vulnerable so that I can inform the webmaster that his/her site is vulnerable. Does that make sense? Joe Caldwell Founder, Indago.info