Gravity Forms User Registration GPL
The User Registration Add-On for Gravity Forms makes registering users, creating login forms, and even setting custom user meta a breeze.
Automatically register WordPress users when a form is submitted.
Our Login Widget makes it easy for registered WordPress users to log in via a widget you can place in any sidebar.
Send notification emails at pre-determined points in the user registration process such as when a user has been manually activated after registering.
Automatically create a new WordPress site in your Network associated with the user that is created.
Populate BuddyPress custom profile fields with form data.
Populate user metadata and create custom WordPress user meta with form data.
When used with the PayPal Add-On you can configure your form to only create the user when PayPal has confirmed their payment.