if the rest of the site is in html, I would go or a CSS Style sheet, and just insert it the rel link into every page, include some DHTML that way you get a kind of flash effect.

Have a look at these examples they both use css

http://intercity.net3services.com/int_current
Basic HTML, CSS, asp

http://intercity.net3services.com/newweb
DHTML, included in an external style sheet

This way I only need to make the change in one location, that change is then picked up, by the html page as it loads, and make the change dynamically.

If its not an external style sheet your gonna have the same problem.

Let me know what you think.

Andy