Multi Level Navigation
The out-of-the-box WSS navigation offers one level of navigation. The navigation elements can be configured in the site settings.
There is a way to make it have multi level navigation, as MOSS does, by changing the DataSource. But this “hack” is not flexible, as you can not reorder the item within the navigation menu.
While I was reading the post How to create your own Cascading Navigation using the ASPMenu control, the decision was made to build a custom navigation which supports multiple navigation levels.