This is a php script that runs outside Drupal to send your Simplenews
You only need the php file and a form that will initiate it plus a custom unsubscribe page. The script uses simplenews newsletter database tables, users, newsletter categories etc. The only thing you have to do is to disable the simplenews newsletter spool cron from Drupal or choose not to send them form Simplenews/Drupal interafce in order to avoid having both this tool and Drupal cron sending mails.
tellmatic is a php and mysql based newsletter script to create, manage and send personalized newsletters or mass mails. uses wysiwyg and has a form editor. adresses and newsletter are stored in unlimited groups. handle bouncemails and failed adresses