You can create a custom menu and add the dynamic Categories pages to it and order then the way you want to.
Please read this first Post vs. Page http://en.support.wordpress.com/post-vs-page/
(1) There is only one page we can post to in any blog.
(2) The static pages http://en.support.wordpress.com/pages/ we bloggers create do not automatically update.
Only the dynamic pages like Archives, Categories and Tags created by the software when we publish a post will update automatically update with new posts.
By default the front page of the blog is the Page that displays all posts in your blog. You can create a static front page and have your published posts display on another page http://en.support.wordpress.com/pages/front-page/ but doing that does not change what follows.
Though there is only one dynamic page in a blog for posts (not pages) http://en.support.wordpress.com/post-vs-page/ and we cannot post to more than that one page, we can create the appearance that we have posted to more than one page.
Create a custom menu
Add dynamic categories and sub-categories pages to it
Create order and sub-menus (dropdowns)
This guide will walk you through how to create category pages for your blog, to display groupings of similar posts on pages other than your front page. http://en.support.wordpress.com/category-pages/