you can use a DHTML menu (floating menu) which is pretty easy to configure if you know enough java script.(Lots of documentaition to help you) Get it here. The Demo is right at the top
pros: this basically allows you to make one change that affects all pages
cons: it sometimes disappears randomly so unless your site is business related i would recommend it.
Just to add a little bit to this discussion, I use a Javascript driven menu on my web site. The menu only exists in one file and is sourced from all of my pages. To change the menu, I only have to change one file and all the pages see the change. I also use the same code on my Site Map to popup information windows. I obtained the original code from Dynamic Drive. There is a section on Menus and Navigation. Pick one that suits your needs. Most of them are pretty easy to modify for your own needs.
