Flash can be used as an element in an html document. One popular use is to create the banner and navigation elements for a site using Flash and then place that Flash in one part of a frameset document.
Here are some screen shots of an example of that. The navigation section has only one button and therefore will only change one document, the procedure can be extended as needed to allow for any number of sections to a website.
You can download the original files for this example and use the contents if you like.