Date: 07/29/06 (Java Web)    Keywords: php, html, apache

This technique will only work if your Apache server has PHP enabled (how to test php support in apache http server) and .htaccess enabled. In the root directory of your html files create a file named .htaccess. The file may already be present. Open the file in your favorite editor and add the following lines: addtype application/x-httpd-php [...]

Source: http://blog.taragana.com/index.php/archive/how-to-run-php-in-html-pages/