Some themes do have dropdown menus from parent pages to child pages and some do not. As you have not linked your username to your blog or provided the URL for the blog we do not know which theme you are working with. Please post the URL for the blog in question so we can provide specific and relavent answers and advice.
If what you are looking for is a website style of blog then that is possible. Staff have provided this support documentation entry. > http://en.support.wordpress.com/using-wordpress-to-create-a-website/
There is only one dynamic page in a blog and we cannot post to more that one page. What’s critical is to understand when creating a website structure the following:
1. The differences between pages and posts and the impact of choosing to restruture a blog to become page based.
2. We organize our posts by use of categories and how to set up custom menus. Although we cannot post to more than one page in a blog we can create the appearance that we have done that by setting up a custom menu and displaying Categories in tabs along the horizontal navigation menu. That feature is available for some themes but not for all themes.
Instructions > custom menus > http://en.support.wordpress.com/menus/
Please read http://wpbtips.wordpress.com/2010/06/30/posts-on-pages/