taxonomy_dropmenu builds a (DHTML/CSS, no javascript dependent) dropdown menu
for selected vocabularies. It allows too to add fixed links, for example, for
Home or Glossary.

The menu is rendered by calling the function taxonomy_dropmenu_buildmenu. You
should have a phptemplate based theme. A example calling code (as a patch) is
provided for box_grey theme

The css use hover selector for some tags other than <a>. That feature isn't
available nowadays in last versions of IE (up to 6 sp1). A javascript trick is
provided to make the menu function even under IE, but, javascript should be
activated.
