Zimbra is the email I am using with norai. I use the open source version and it is the best email experience you can have.
They have announced that VMware has bought email and collaboration software developer Zimbra from Yahoo. Rumors of the sale have been floating around for some time now but the writing was on the wall when Scott Dietzen, former CTO of Zimbra, quit Yahoo last fall.
Yahoo bought back in 2007 zimbra for $350 million.