Suckerfish menus
Some other suckerfish menu links to explore, will try some out in drupal and see how they work ?
http://www.digifuzz.net/archives/2008/06/suckerfish-style-menus-in-drupal-6x/
http://www.digifuzz.net/archives/2008/06/suckerfish-style-menus-in-drupal-6x/