Ok, just used the .htaccess in the FAQ section, and stopped some hotlinkers.

But I have one domain that I use for picposts, so I want to allow some domains to hotlink me. How do I modify that .htacess to allow that?
this is what I have
ErrorDocument 404
http://www.mydomain.com/404.shtml
RewriteEngine on
RewriteCond %{HTTP_REFERER} !^
http://(.*@)?([a-z0-9-]+\.)*mydomain\.com(:[0-9]+)?(/.*)?$ [NC]
RewriteCond %{HTTP_REFERER} !^
http://(.*@)?1\.2\.3\.4(:[0-9]+)?(/.*)?$
RewriteRule .*\.(asf|mpg|mpeg|wmv|avi|rm|gif|jpeg|jpg|zip)$ - [NC,F,L]
how do I add in domains to that that are ok to hotlink?