hMailServer

Homepage: http://www.hmailserver.com/
Supports: ClamAV
hMailServer is a free, open source e-mail server for Microsoft Windows. It supports all the common mail protocols and comes with a easy to use COM library that can be used for integration with external software. It also has supports for virtual domains, distribution lists, ClamAV, aliases, distributed domains and much more. E-mail data is stored in a database server, MySQL or MS SQL, depending on your choice.