You could make a seperate links page, eg links.php, and then include that in your pages (this is that I do).
So, you haev your links.php file and in it you type:
<a href="index.php">Home</a>
<a href="design.php">Design</a>
<a href="contact.php">Contact Us</a>
<a href="about.php">About Us</a>
Then, you have you individual page, which are just regular php/html pages. In the place where you want the link to be, you use the "include" command of php:
<p>this is my page....blah blha...</p>
<p>click the links below to tour the site:</p>
<!-- include links.php file here -->
<?php include("links.php"); ?>
Obviously, you will want to make it look pretty etc
This works well for me, and is very simple. This way, when you add a new link, just add it to the links.php file. It will change on every page.
Hope this helps.
Hamish