Hi,
The only relevant settings are:
Require Approval Before New Users Can Sign In?
Email Addresses(es) For User Approval Notification
There is no separate setting for notifying the user, notification of the user is assumed to be needed if approval is required. When the admin gets the notification of the user having registered he follows the link in the notification and clicks the button to approve the user and an email will be sent to the user letting him know that his account has been activated.
Hope that helps,
Joe