Automatic Navigation Hierarchy for Content Pages

Simple but powerful...
WSS/MOSS allows an extensible Navigation system.
At times we need to display the hierarchy of pages. For example:
Articles Landing Page (shows a List of all Articles) --> Each Article is a page of its own.

Solution:
Create a subsite for Articles. Set the home page as Articles Landing Page (from site settings --> Welcome Page). Also set the navigation to show Pages
Now on the quick navigation on left

it will Show the following in Navigation
Site Name (which links to Landing Page)
Individual Article Page1 Title
Individual Artcile Page2 Title

That works Good. How about having Multiple Categories:
Category (each category is a site with Home Page) --> Sub Category (each subcategory is a Page only)

Hence we will see the navigation as:
Category 1 (site with a home page)
Sub Category 1 (page)
Sub Category 2 (page)
Category 2
Sub Category 1
Sub Category 2

So in above case we only created two sites i.e. for Category 1 and Category 2 and the remaining are content pages.

What if there were 3 levels;

Level 1 (site 1 with a Welcome Page)
Level 2 (site 2 with a Welcome/Home Page)
Level 3 (pages below Site 2)

Hope this helps...
Mohan