How I can make this?

[CMGU]

How I can make so that people that want register in my forums
only they can register with the following email.

@hotmail.com
@yahoo.com <= it includes all the yahoo
@gmail.com
@aol.com
@msn
@netscape
@aim

please help me!!

[Weapon-x]

Why limit your users to register.

I have a whole list of emails you should block if you want just private message me.

[CMGU]

ok i sent you a message