MailMailer Software Description:

MailMailer is a compact easy to use server (web) based email mailer. It is specifically designed for the small business market, not to be the biggest or most featured but to be a clean efficient contact tool helping you to send newsletters to your clients, contact your staff, send one email or many.
Key Features - compact size (7 kb download), ease of use, web based (just upload to your web host), clean (virus free) text emails delivered from your server not your computer, real time Send Status, capacity to load default Mailing List and Email Body from server, web based access (you can send from anywhere), accepts Mailing Lists in comma separated format, provides mail merge for contact NAME.

All you need is a web browser and a web server that supports the php scripting language (included on most commercial servers) and you are up and running.