I've been running BlueQuartz as a replacement for our Cobalt Raq hosting servers. It has worked well. About a year ago I decided I needed Openwebmail for it. The package didn't exist so I wrote something. Works well. If you host you might find it worth while. I also have a ClamAV package for it also.
http://home.lewiscounty.com/~forhire/owm.html