libsmtp does this, but its MIME support is experimental.

The interface is simple and clean.  It is a client, of course,
that requires you to specify a mail server that it will use.

If you use it, I have some patches I haven't yet fed back
to the developer; contact me.

Vic

"Furmanek, Greg" wrote:
> I was wondering if there is a library in c
> that allows for sending e-mail from a running
> program.