Do I need to buy WPMU?

We’re in the process of setting up a local online newspaper using the theme found at http://www.wpnewspaper.com/advanced/

Totally green to this all, so please excuse the beginner questions. I already posted under the new jobs offered section looking for folks to help us set up.

This newspaper will have columns and sections written by different people. I want to have admin control over the whole site but have individual writers only have privileges for the pages they edit.

Is this something I would need to purchase WPMU or or is that capability built into the regular WP.

Regards

Steve