hi Nathan,
php and mysql are opensource and free to use you only need mysql if your website uses databases.php can be download from http://www.php.net and mysql http://www.mysql.com if it is just for form handeling you don't need mysql however if the form(s) uses a database you will need it
you can print the phpinfo to your browserscreen like this
<?php
phpinfo();
?>
if your server is apache you can install php in ywio ways the cgi executable or the module since both ways are different refer to "install.txt" distributed with the php package for help on how todo this
regards