My primary navigation is hard coded (it has to be; graphical purposes).

Firstly, how can I tell which one is "active" (current page)?

Secondly, based upon which one is active, how can I show child links of that link in the sidebar? I've thought of a possibility, but it would require creating tons of blocks for the menus and then only enabling them on their parent page. This seems like a lot of work for something that a module should take care of.

I've found http://drupal.org/project/menu_block which looks promising, but I'm not clear how to use it in my situation.

I prefer to have total control of how the menus will look (a custom .tpl file)