[support] Getting clean url's

I have a drupal instance on my server and as far as I can tell Apache is configured for mod_rewrite but when I try and configure Drupal for clean URL's it doesn't seem to pick it up. I do have the .htaccess file that came with drupal in the the /var/www directory which is the apache document root. Any ideas on how to get Drupal to recognize the clean url's?