Updating pages dynamically

I'v made a website template for a client in Photoshop and I want to be able to dynamically change the pages from an admin area.

For example, I have a news page. I'd like to be able to throw in an "include 'news.php';" line into that page that will display the text that the client types in from an interface in the admin area.

To clarify:
Client logs into admin area.
Client has the option to edit the existing pages (news, etc..)
The client edits the file and then saves it.
The file that they edited is included in a static page.

Let me know if there is a script that will do this (either with mysql or text file).

Bump...

There is 1 option for this and should be easy to program with little php knowledge:

1. Have a database which stores all the text. e.g. the following structure:

id
pagename
pagetext

On your admin panel you then have a textarea which when submitted will run a mySQL query to update these tables. Then you have a simple check on each page to select data from the database so that is relevant to that page and echo it back out.

If that didn't help I don't think I understood your question :/