A simple mail server for testing. From: http://djangosnippets.org/snippets/96/

mail.py

from datetime import datetime
import asyncore
from smtpd import SMTPServer

class EmlServer(SMTPServer):
    no = 0
    def process_message(self, peer, mailfrom, rcpttos, data):
        filename = 'mail.eml'
        f = open(filename, 'w')
        f.write(data)
        f.close
        print '%s saved.' % filename
        self.no += 1


def run():
    foo = EmlServer(('localhost', 25), None)
    try:
        asyncore.loop()
    except KeyboardInterrupt:
        pass


if __name__ == '__main__':
    run()