Are you looking for multi-user blog ? Consider WordPress MU (multi-user) blogging application, it is the multi-user version of the WordPress blogging application. It is ideal for people who want to set up a large network of blogs. Multi-user blogs will help users to contribute news and industry information with multi-user capability.
Beauty of WordPress MU is that plugins and themes are controlled by a central system administrator, with unlimited blogs and unlimited authors on them.
WordPress MU used by newspapers, magazines, Universities, blog networks, universities and large companies.
For more information check out WordPress MU website.