Looking for Lightweight Email Transmit Agent

I only need a transmitting part of an email server. Is there any
specialized application for this?
It should not use more then a handfull megabyte ram because it has to
run on a very small virtual server.

Recommendations?

The carbonbased lifeform scholz.lothar-at-gmail.com inspired comp.unix.admin with:
> I only need a transmitting part of an email server. Is there any
> specialized application for this?
> It should not use more then a handfull megabyte ram because it has to
> run on a very small virtual server.
>
> Recommendations?

ssmtp