GUI Web Page Updater/Modifier

This seems like it would be a commonly asked question but upon searching the forum I found nothing, but feel free to batter me with links/lectures about searching for things better(that usual does the trick).

I’d like to know how to setup a system where my boss can easily update the text on several pages of our website with a form of sorts (probably password protected which i can make happen). I assumed that this would be done with XML/PHP/MySQL, or a combination of the three but after learning the basics of XML(from W3c.com) i really haven’t seen any light at the end of the tunnel.

Any help is appreciated

Thanks