Decided to open up the site to User Registrations after doing yet another code audit. Just click the Register link on the bottom menu. A valid email is only required if you forget your password as that is the only way to reset it.
User mailboxes are being coded now and at first will only allow messages to/from admins. In the future as more social features are added, users will be allowed to message each other with attachments if they opt-in.
Usersites are expected to be added after the mailboxes are fully implemented. Think of them as 1 page sites with file uploads allowed.