Yes, there are a couple of ways to go about it. You're essentially talking about an "include" or something that behaves like an include.

Which way you choose to do it will depend upon how compatible you want the site to be. There are ways to do it in the page code if your users have a recent browser.

But if you want it to be compatible with all broswers including very old ones, then you have to do it all server-side. The www.riocar.org site is an example of this. Its left-hand navigation menu can be easily updated without having to make a change to all of the pages. There is a piece of software running on the web server (in this case, PHPNuke) which handles all of the updates to the left-hand navigation bar.