RewriteEngine On
RewriteCond %{HTTP_USER_AGENT} Googlebot [OR]
RewriteCond %{HTTP_USER_AGENT} AdsBot-Google [OR]
RewriteCond %{HTTP_USER_AGENT} msnbot [OR]
RewriteCond %{HTTP_USER_AGENT} AltaVista [OR]
RewriteCond %{HTTP_USER_AGENT} Slurp
RewriteRule . - [G,L]