Using SSI would require using the .shtml extension and does slow your server if you get heavy traffic. You'll also need to code it differently on Windows or Unix. On MX go insert > script objects > server side includes
php is easier! If you get DW resource kit 2 or 3 (can't recall which but the macromedia site will tell you) you get the extension for it, otherwise the code is simple anyway:
Code:
<? php include ("NAMEOFYOURPHPPAGE.PHP"); ?>
That's quite easy to work with even if you hand code it.
Dani