This will protect *all* formats of video files, even WMV. The catch is it does require both cookies and javascript - so if your surfers have either disabled they won't get the movie.
.htaccess file:
===============
RewriteEngine on
RewriteCond %{HTTP_COOKIE} !(^|(.+;)*)id=valid(;.*|$)
RewriteRule .*$
http://www.yourdomain.com/cheaters.html
javascript to set the cookie:
=============================
<SCRIPT language="JavaScript">
document.cookie = "id=valid; path=/"
</SCRIPT>
Instructions:
=============
1) Add the javascript to the <head> section of the document containing the links to your videos.
2) Modify the .htaccess code above to reflect your proper domain and page to redirect hotlinkers and place it into your directory/folder containing the videos you want protected.
3) Upload the files.
4) HUGE PROFITS!