Miaz Akemapa

Regnomail is a plugin to customize your registration form. It disable sending email confirmation during user registration to admin and to user itself.
Regnomail Features:
<ul>
<li>Disable email confirmation to user during registration</li>
<li>Disable new user email notification to admin</li>
<li>Disable user change password notification (lost password) to admin</li>
<li>Show password input form, so user can input their own password</li>
<li>Show First and Last name input form</li>
<li>Change login / registration logo image.</li>
</ul>
Read more details here: 
<a href="http://www.vnetware.com/regnomail" rel="nofollow ugc">http://www.vnetware.com/regnomail</a>

Regnomail

Disable new user registration confirmation email.

shawfactor

This plugin allows you to turn of or shutdown registration via Buddypress, without effecting other functionality.
I built this as I don’t like the way Buddypress does registrations but liked most of the rest, but you could use it if your site was full or invitation only for instance.

LH Disable BP Registration

Shuts down registration via the usual Buddypress method, all other functionality is not effected.

Regnomail vs LH Disable BP Registration