ie6 will not display the hover in this type of menu, but you can include some javascript for the css as explained here http://www.htmldog.com/articles/suckerfish/dropdowns/
or upload a htc file to the server and reference that.
The tutorial for that can be found at http://www.xs4all.nl/~peterned/csshover.html and you can get the htc file from http://www.xs4all.nl/~peterned/htc/csshover2.htc
