Content Management Systems (CMS) typically provide a Web 2.0 publishing environment that permits non-technical folk to update and publish content on a web site, without the need to use specialised web editing software.
However, in my experience, CMS software itself is reasonably complicated to set up. Joomla, Mambo, Drupal, ModX, TextPattern, and the zillions of other CMSs that are available for free, all provide an easy publishing environment for the end-user, but they are not that easy to configure for the casual user who has been thrust into the role of system administrator - a place where many teachers find themselves.
The links below provide information about how to configure WordPress to create a more traditional (non-blogging) web site, and to use it as a psuedo CMS.
Here are some examples of school Intranet / Internet sites created using WordPress as a CMS: