Did a quick search and didn't see another topic on this one.
Evolution is a free package from Novell, and is available for Windows based systems as well as Linux systems. I find it to be nicer than Thunderbird because of the Calendar integration - in fact it looks very much like Outlook, only far lighter and faster.
Is this one a possibility?
Also - thanks for all the hard work - you do excellent stuff on this site!
Trib4l (aka Kevin)