phplist is an open source newsletter script, which includes multiple mailing lists and attachments. Other supported features include: RSS, click-tracking, scheduling, etc. phplist is free to install and very easy to integrate with any website.
Many of our clients use it because it is free and offers many options. On our hosting platform it can be installed automatically using
Elefante Installer - just one click is needed from you to install phplist, as well as many other PHP scripts