Deep Linking - Finding Best Method For Website Where User Can Create Articles (like A Blog)?

I'm an ASP.NET newbie, but not so new at programming in general.

I'm creating a commercial website, and I want to allow an admin to add new articles (an article consists of text, images and various properties such as category).

I am trying to decide the optimal Modus Operandi. This site is commercial, so SEO is a major consideration. This means that I want each url to be "unique". That is, if someone navigates to an article about raccoons, he should be redirected to [URL]. This means - I can't have one page that loads the appropriate article dynamically a-la AJAX (gotta use deep-linking)

So how exactly do I do this? suppose the admin entered his text, uploaded the images and set the article properties. I create a new subfolder, save the images to the server (I understand that saving images to a DB is a big no-no), their addresses in a DB, and the content itself to the DB. But now what?

How do I go about creating the actual page?

Is there a function for creating a new aspx file? then what about its corresponding cs file? Or is it unwise to use aspx? Maybe plain html? but then how does it work with my site's master page? Or maybe just create another copy of a general aspx file which is populated with an article according to a parameter?