It is a mass mail sending tool. You can use a text formatted file or a MySQL database for mail sending list. It is open source and GPL licensed program written with Lazarus and FreePascal.
You can download Win32 binary. MacOSX and Linux binaries are welcome. These programming tools and libraries used for development.
Lazarus : http://lazarus.freepascal.org
Synapse : http://www.ararat.cz/synapse/
Synapse already included in source code directory.
It is licensed under GPL license.