template system suggestions?

Hi folks, Can anyone suggest a starting place, i.e. existing code that will: Generate a site, complete navigation links and webpages depending by pulling mysql content into a page templates? I'd like to provide behind-the-scenes admin pages too, for an admin user to create a new page by filling in a form with information such as a description, img to upload, what category to put the page in, etc., and even allow creation of new categories that would add links to the navigation menu, etc. Seems I've seen this sort of thing discussed, but I cannot find any references to it. TIA, Andrew