Newsletter Sign-Up is a WordPress plugin by DvanKooten that adds a checkbox to your comment form that allows people to subscribe to your newsletter.
This plugin currently supports the following newsletter providers but is not limited to those: Aweber, Mailchimp, iContact, PHPList, Feedblitz. You can practically use the plugin for EVERY newsletter provider that’s around if you use the right configuration settings.
Add a “sign-up to our newsletter” checkbox to your comment form
Add a “sign-up to our newsletter” checkbox to your WP register form
Add a “sign-up to our newsletter” checkbox to your BuddyPress register form
Specify additional data to be sent to your newsletter service along with the sign-up request
Subscribe the commenter with their name
Hide the checkbox for users who used it to sign-up to your newsletter before
This is the continued and much better version of Qoate Newsletter Sign Up, offering much cleaner code, better performance and much more.
Plugin homepage: http://dannyvankooten.com/wordpress-plugins/newsletter-sign-up/