Email Piping

I'm in need of a script design where POP3 specific email will come in, the script must parse the incoming text-based email ( specific format always), about 12-20 variables. Then I will need the scripts to SMTP this using an HTML-based template and send it back to parsed email address. Cron Job will run every 3 minutes. Must document code, as we expect the original email format may change in the future.