massmail is a Drupal module available for Drupal 5 and Drupal 6.

The massmail module enables users with the proper permissions to send an email message to all users on the system. Users are opted in by default, however, they can choose to opt out either by editing their user account settings or by clicking on a link automatically appended to every email sent which provides them with a one click opt out option. In addition, this module provides a subscribe block that allows users not logged into the system to subscribe, which behaves like a normal email list subscription process (users are required to confirm their email address), however, behind the scenes it automatically creates a user account for them.

There's both a Drupal 5 (massmail-5) and Drupal 6 (massmail-6) version available.

massmail-6-0.11.tar.gz
Posted Thu 06 May 2010 06:21:22 PM EDT
massmail-6-0.9.tar.gz
Posted Thu 29 Apr 2010 10:36:28 PM EDT
massmail-6-0.10.tar.gz
Posted Fri 11 Dec 2009 06:48:09 PM EST
massmail-5-0.9.tar.gz
Posted Fri 04 Dec 2009 03:42:10 PM EST
massmail-6-0.8.tar.gz
Posted Fri 04 Dec 2009 03:42:10 PM EST
massmail-5-0.8.tar.gz
Posted Thu 23 Jul 2009 01:22:52 PM EDT
massmail-6-0.7.tar.gz
Posted Sat 18 Jul 2009 07:11:31 PM EDT
massmail-5-0.7.tar.gz
Posted Sat 18 Jul 2009 07:11:31 PM EDT
massmail-6-0.6.tar.gz
Posted Sat 09 May 2009 10:38:59 AM EDT
massmail-5-0.5.tar.gz
Posted Sat 09 May 2009 10:38:59 AM EDT
massmail-0.5.tar.gz
Posted Thu 19 Feb 2009 11:31:26 AM EST
massmail-0.4.tar.gz
Posted Sun 08 Feb 2009 07:25:42 PM EST
massmail-0.3.tar.gz
Posted Sun 08 Feb 2009 07:16:45 PM EST
massmail-0.2.tar.gz
Posted Fri 07 Nov 2008 09:56:44 AM EST
massmail-0.1.tar.gz
Posted Thu 06 Nov 2008 05:01:06 PM EST