To install:
First, make sure you have installed phptemplate. The given patch is against
the distribution box_grey theme.

1) Create directory taxonomy_dropmenu under Drupal modules/ directory.
2) Copy all files to it
3) Apply the given patch to your box_grey page.tpl.php
4) On your Drupal site, go to administer > modules and enable 
   taxonomy_dropmenu module.
5) Go to administer > settings > taxonomy_dropmenu and select with
   vocabularies you wish a dropdown menu get generated. Optionally you can
   define fixed top links.

The main problem now is that the menu width is fixed for every menu, set up
in the CSS. You should update it to make width enough to contain your lasgest
menu item. I'm currently looking for a way to avoid that.

You can look for the string 'CHANGE MENU WIDTH HERE' in the css.
