Even if you go into your google webmaster tools and request that the pages be removed - it clearly states that unless you take measures to stop the indexing, the pages will get indexed again. So even if you ask google to remove the page, its still going to be indexed again.
You could use htaccess and htpasswd to password protect the directory. Just do some google searches for htpasswd and you should be able to find something. I'am using this same method to protect a backup script for my sites.
Once you have the file in place, when someone goes to view the site, or any directory that is under the .htaaccess file, they will be promoted for a username and password.