Sorry to revive this old post but I ran across it while looking for something else and thought it may help someone.
free version of PostCast is SMTP only
http://postcastserver.com
Have used this on several Windows/Abyss setups where php.ini needed an SMTP server for sending mail from website.
Have also have used it on several Abyss/Joomla systems for allowing Joomla sites to send mail.
Install PostCast on Windows/Abyss server
modify php.ini
[mail function]
; Setup for Windows systems
SMTP = 127.0.0.1
sendmail_from = me@myserver.com
Follow PostCast security recommendations to prevent being used as an SMTP open relay.
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