I have this in my .htaccess (modified from the default Drupal .htaccess):
RewriteCond %{HTTP_HOST} ^www\.website.com\.com$ [NC]
RewriteRule ^(.*)$ http://website.com/$1 [L,R=301]
In theory this will redirect something like http://www.website.com/asdf
to http://website.com/asdf
. However, it doesn't redirect, it allows requests to go through like there was no redirect intended.
(I'm on OS X if it matters, but I've also tried it on a Network Solutions Linux server with the same result.)