You can do this with the built-in menu system in WP3.0+. If your theme doesn’t support it, you can add support-
http://www.devlounge.net/code/how-to-add-support-for-menus-in-your-wordpress-theme
that is a decent tutorial about adding menus, but my goal is adding a menu ITEM that points directly to a post. Even more specific, i want that menu item to be a sub-menu item inside a categories type of a drop-down menu.
That’s possible using a custom menu.
we’re getting closer to it, unfortunately I need this to work for WP 2.9.2
want that menu item to be a sub-menu item inside a CATEGORIES type of a drop-down menu
The only way to do that is to roll your own category menu using get_categories and then insert your custom links as you loop through the returned array to generate the displayed dropdown list.