Plugin for managing subscriptions to a mailing list. It provides a simple form for subscription to your mailing list through single or double opt-in.
The wpsb-opt-in.php file must be in the
/wp-content/plugins/ folder and not in a subdirectory.
Yes: to have the newsletter widget inside a post you must enable PHP execution inside posts. First install this PHPexec plugin:
then write this code in your post:
<?php wpsb_opt_in(); ?>