Under "Integration Guide", we have tried to list couple of well known SSO configuration POC setup. It should be good to start I believe for you.
>> I have created a site outside of the Wordpress one in PHP and was wondering if it was possible to actually integrate that same SSO style into my own site?
Possible. First you need to find out if there is any openid connect plugin for PHP site or not. If there is plugin, you can put that infront of your php site.... that plugin would connect with Gluu Server.