PHP and APACHE & VirtualDomains

We have PHP and APACHE (1.3.19) installed and an instance of apache is running with php support enabled. I need to set up another instance of httpd using a seperate config file. However I cannot get PHP support enabled. I cannot find where the PHP modules are. I called a phpinfo() on the instance which is already running and it returned: It said the config file was in /usr/local/lib/php.ini I think i am looking for the module mod_php4 but I cannot see where it is. Any ideas? ALSO I'm having lots of trouble with VirtualDomains. I have an instance second httpd running (without php) on a port other than 80 and it runs fine. But whenever I add VirtualDomain to the httpd.conf the main page gets replaced by the main page of the VirtualDomain. This is really anoying me is there anything I should check for? Thanks