Hello,
I'm interested in your project. I have more than 7 years of experience in hosting environment. I glad to say I have experience on various mail servers such as MS Exchange sever, Hosted MS Exchange, Smarter Mail, Hmailserver, MailEnable, IceWarp, Zimbra, Dovecot, Exim, Postfix, Sendmail etc.
On windows platform, there are several free mail server application such as Hmail server, Mail Enable which is easy to integrate with free website panel. If you looking for the security side, then I would recommend you to go for SmarterMail.
Let me know when you would be available, so I can assist you.
Hope my bid is lower than other freelancers :)
Thank you,
Jagdeep Gill
Skype Jaggyd86