Verifying users

I'm creating a blog which allows users to self-register as a commenter. I have two questions:
Is there a way to put a newly registered user in moderation when they first register so I can review their posts for a while before others see them?
Is there a way I can request their email address when they self-register and then send an email with a link they have to click to complete their registration?
I see there's a configuration option to "Check email or site before posting", but as a self-registered user(Commenter) has not provided an email address how does this work?
Thanks so much,
Tony