well, you could go a few routes, using a htpasswd and htaccess combo or using a php/cgi/whatever script to require logins... check hotscripts (dot)com for the latter (rofl 5th post is the one I happen to decide to post a url on)
Well I'll look at that hotscripts site right now. Just to expand on what I'm looking for:
You can't get access to the website whatsoever unless you are logged in. In order to create an account you need an invitation code, which I can make as many as needed. I'd love to get my hands on those crazy codes gmail uses.. the look impossible to guess at.