[Plugin: DantoTube] Multiple Blogs/Users in one site

Sorry if this has been covered but I didn’t know where to start. Here goes. I have a website that will feature multiple posts on various topics contributed by multiple bloggers. The bloggers will have different permission levels for contributing, e.g.; 1x month, 2x month, 4x month, etc… Are there any plugins that will help me manage the multiple bloggers with various permissions?

The “Our Bloggers” section of this website is a good example of what I am trying to manage: http://www.mnn.com/

Thanks.

http://wordpress.org/extend/plugins/wordpress/