Me again Trevas.
The email is simple. Send FaithWriters a message letting them know you are a 500 member and would love to use the free FaithWriters email. Make sure you let them know the user name you want to use (the bit that will go before the @faithwriters.net part) and your choice of password. They'll activate it and get back to you.
Here's the contact form to send a message to FaithWriters: