Does anyone know what to add in the .htaccess to enable PHP in a subdomain hosted on a server with Plesk?

www.domain.com/~subdomain

Took this from a new FAQ and it is a little different from your question. Hope it helps:

How do I enable webusers to use php?
This is possible by adding the following line in the domain's vhost.conf file:


php_flag open_basedir "/usr/local/plesk/apache/vhosts
/<domain>/"


(remember to swap out <domain> with the domain name)


If this file has not yet been created it needs to be created in the domain's conf directory /usr/local/plesk/apache/vhosts/<domain>/conf/. The ownership should be root:root and permissions 400.


Once the file is saved the following utility must be run in order for the changes to take effect:


/usr/local/plesk/admin/utils/my_apci_rst

Thanks,

Adam Williams