Mailserv is ambitious project to create a database-based mail server. What I eventually have in mind is server software with the great features that are available from Microsoft Exchange except with software that is open-source and based on Internet standards. The license for mailserv is the GNU Public License.
The inspiration for mailserv came from gmail, which is a GNOME mail client that saves its mail in a MySQL database.
For my development platform I'm using Linux. I'm currently running RedHat 6.2 beta on my laptop. For the database I'm using MySQL 3.22. I'll soon be upgrading to 3.23 or later, because they've recently moved MySQL over to the GPL!
I've set up an account on SourceForge for mailserv. You can go to the project here. I've uploaded the mostly non-functional 0.1 pre3 release there.
Initially I'm doing all of my testing of mailserv with pine. Eventually I'll start using Outlook Express and other IMAP clients.