Need a script (no design) where user has 2 ways to sign up:
1. If he has invite code, he can sign up using facebook. He will then see list of friends (table form, with checkbox to select) and he can then invite selection of friends to participate, and they will be sent code to news feed or private message (user can choose).
2. If visitor does not have invite code, he can only apply for access using facebook login and only when admin agrees, he gets accepted and is sent link to function so he can choose friends to invite using a code.
Admin sees list of users and they can be accepted or not accepted. If admin accepts a user, he gets sent confirmation and link to function that he can use to invite his friends.
1. Signup/login page
2. Invite friends function
3. Admin page to see all users and accept those who apply without invitation
Such scripts have been done multible time, if you posess show it with link.