Horizontal Nav & SubNav

Hi there,

Could someone please help me to setup my nav. I just need the major categories horizontal, and the sub-categories underneath. Kindof like how the Admin area looks… nothing fancy, just when you’ve selected your category, it goes to the first sub-category page, and you can see all the other sub categories.

So in a way, kindof like how Digg.com has itself setup with 2 simple horizontal nav bars on top of each other. But this wordpress one would show the categories on top, and the list/pages for each category in the bar below.

I can do the styling later, but i just need to get it looking cool.
Trying to do it like this: Click here

Thanks heaps,
Glen