Sounds like a Content Management System ("CMS") to me. There are specialized systems like
wordpress which is primarily used for weblogs or
phpbb which is primarily used as a forum. Then there are more general and much more complex ones, like
plone or
drupal.
Or you sign up to one of the many online free blog services. This might be the easiest way to get started, because you won't have to install anything, just give away your email address

Some can be filled with content by web form or
desktop software; others require only
a set of GNU tools, or even less: only the
bash shell! (Check
their project goals too)
Note: the links I provided are only examples of software; there is much much more, so much more, you might be overwhelmed by choices. Which leads me nicely to my question:
Can you tell us what you want to accomplish besides editing your own pages?