There is stuff you can add to your site and your bots.txt file
*Cough* It's called robots.txt..... and it's a double edged sword.....

If you think you can hide stuff from google etc. by placing it in the robots.txt file remember that a cracker will look to see if you have one... It has to be publicly available and it shows those things you want to "hide"..... Obviously an interesting file.....