Email as Username in registration

Hello,

many users would to allow the registration in a wp site without an username, just only with an email.

This is a core problem, so the solution is to replace username with email.

If wp requires an username and an email for the registration, we can get email value and put it in username value. In the registration form users will see two fields:

1. your email
2. repeat your email

This is a trick, because for wp the real fields will be:
1. username (as your email)
2. your email (as repeat your email)

Can this plugin do this?

Thank you in advance!