Running scripts in non-php file

Hi folks. This will probably sound like a stupid question, but I will ask it anyway: how can I get the PHP interpreter to execute scripts in files that don't have the .php extension? i.e. if I want to embed php code into a .html or .xml file that gets run. I thought all I had to do was add the extension to the AddType application in the apache configuration file so it looked like this: AddType application/x-httpd-php .php .html .xml I tried it but the code isn't being executed. (And yes, I did restart apache) Am I missing something? Tom