MailBlaster is an easy way to create and send mail to groups of addresses. It is easily tweaked for individual needs. It includes a list manager, wysiwyg html message editor (htmlArea), and an easy to edit config file. It uses PHPMailer as it's transport class.
WYSIWYG HTML editor allows you to create HTML Rich messages without HTML
List Manager allows you to maintain as man different mailing lists as you need
Ability to save messages so you can open them later
Removal links in e-mails so recipiants can remove themselves from your mailing list