CMS = content management system. If you are hosted here at astahost, you can install them through cpanel under the Fantastico menu and will be ready to go. Basically a CMS (such as freePhP, Drupal, Mambo Open Source, php-nuke, etc) lets you build a webpage and update content quickly and easily.
Once you install a CMS, they usually/always have a basic template style. You can either obtain generic templates from their site or other sites to use, modify an existing template, or make your own. This basically is the design and layout of your site.
Once you have a template created, you can basically log in and simply click "add content" (or something similar) and add a page. A CMS allows you to take a blog-like approach to a webpage. It keeps news posts and sub pages all organized for you and you simply use online forms to make the various pages of the site.
This would be great if you have employees that need different levels of access, as you can usually give each username it's own level of access. Some may be able to create/edit all posts, others only submit news posts that need to be accepted by higher ups. A CMS system allows you to make a site that is 100% congruent, easy to manage, and well organized. You basically can keep it updated completely with only accessing it through web interfaces if you so choose (after you have a template set up).
For more info on a couple popular CMS options:
PHP-NukeMamboDrupal <-Note: Drupal's site was not responding when I posted this...
Comment/Reply (w/o sign-up)