I want to set up m y web page so that if I edit anything on a nav bar I only have to edit it in one place, and not on other pages. How do I do this?

You could go about this a couple of ways, depending on what scripting languages you are going to use. If you are using a server-side language such as PHP or ASP, you could use server side includes or database interaction to integrate your nav bar from a single location into multiple pages.

If you are using straight HTML, you could employ the 'old-school' method by using frames to create a navigation pane. The W3C has a good tutorial for learning about frames here.

Thank you for your advice, I'm using Dreamweaver and Fireworks, so I think I'm going to use the Frame set way. Thanks again

Why not use a template within Dreamweaver. With that, you make how you want all o fyour pages to look (provided the design is the same). You make an editable region within the templated page that will house your page content. When you update your nav bar, you do it on the template and it will update all of the pages that the template is applied to.

I use javascript for my navigation and then simply call the script from each page.

That way I only need to update the javascript file.