.htaccess - this works for me.
RewriteEngine on
RewriteCond %{HTTP_REFERER}
http://.*yahoo.com/.*$ [OR]
RewriteCond %{HTTP_REFERER}
http://.*sexy.yahoo.com/.*$ [OR]
RewriteCond %{HTTP_REFERER}
http://.*64.*.250/.*$ [OR]
RewriteCond %{HTTP_REFERER}
http://.*216.*.250/.*$
RewriteRule ^(.*)$
http://www.hotmail.com [R,L]