SendEmail is a lightweight, command line SMTP email client. If you have the need to send email from a command line, this free program is perfect: simple to use and feature rich. It was designed to be used in bash scripts, batch files, Perl programs and web sites, but is quite adaptable and will likely meet your requirements. SendEmail is written in Perl and is unique in that it requires NO MODULES. It has an intuitive and flexible set of command-line options, making it very easy to learn and use.
You can chose what server you want to send via, from addresses etc.
http://www.caspian.dotconf.net/menu/Software/SendEmail/
or Via Macports