Just found a snipet of Apache configuration that I suspect I might want to use in the future...

It enable you to disable direct linking based on the refer....

SetEnvIfNoCase Referer "^http://www.yourdomain.com/" local_ref=1

Order Allow,Deny
Allow from env=local_ref

Order Allow,Deny
Allow from env=local_ref

Other good stuff I migth want to look into...
http://www.vbulletin.org/forum/showthread.php?t=62003