It seems we can block email domains in our ACP, but this is nearly impossible with the thousands of free email domains such as yahoo and hotmail. I'd like to see a featue in my acp where I can allow which email domains are accepted. if a user registers with an email that reside OUTSIDE the specified email domain, then they will get put into a queue for admin approval (like the current queue for validating members).

Whats wrong with free Email Accounts. Just make all users validate thier email Addresses.

One of my site is a forum for my college. when I ban users, they come back by using a free email.

My school (like most schools) allow only one email per student. this way users are more willing to behave since they know they cannot register again once the email is banned.

Ah, I see what you're saying. A way to make all e-mail domains other than your school's go through an admin validation process.