butchjohn,
The title of your post referred to non wgt members, so I assume you were inquiring as to how to invite them to wgt?
I'm not sure that wgt has a built in app for this, so probably just best to refer them to the wgt main page (www.wgt.com) and ask them to let you know when they have a player name created, then you can ad them to your friends list and be able o see when they are online and ready to play.