I found this little tidbit, but don't think I want to use this method, but is yet another option.
(seems like a bandwidthe burglar)
You can run PHP code in .html files. If you add:
AddType application/x-httpd-php .php .html
to your .htaccess file, all pages with a .html extension will also be parsed by PHP. So you can keep your current .html pages, and add PHP code to them.
I am not concerned about the footer or header being search engine friendly. So I guess frames.
