Website Revised
I helped my daughter and her project team setup a website (http://www.globalconstruct.info). In the process, I did another brief survey into web site creation / maintenance tools. I've experimented with a few different tools in the past -- Joomla, Mambo, phpBB -- but they seemed like a lot of work for a simple site. This time around I found something called concrete5 (http://concrete5.org) that seems a lot easier.
The basic term is "Content Management System" or CMS. Usually this allows separation of content and layout, support for multiple authors, and some kind of version control or database support.