I wrote a couple of libraries for POE, a portable multitasking and networking framework for any event loop written in Perl
POE Component Client SMTP
An asynchronous SMTP Client for POE
Download the SMTP Client. You will need to have a Perl interpreter installed.
POE Filter Transparent SMTP
The filter can be used independently of the SMTP Client for encoding/decoding data to be sent/received on/from the wire.
Download the SMTP Filter.