Has anyone used CSS dropdown menus and if so are they fully indexable by SEs? For example look at the dropdown for www.parabio.com. They are indexed in Google but that could be because of the internal links on the pages for the main headers. Yahoo only has the main header pages indexed.

I'd love to be able to use dropdowns to clean up the look of the nav on a client's site but I'm leary of doing it since the nav links are keyword based and I want the anchor text to get indexed. Unfortunately it is an eye sore without the dropdowns.