MS Exchange is a SW where a central server connects many users via a single interface that typically a web or email client, which enables users to share contacts, notes, to-do lists, scheduling and calendar information, as well as act as an email client. It is the big brother of OE, which is wind’s default desktop email client. However, why r u stuck up, don't know, but Evolution / Thunderbird / Zimbra Desktop or even IBM Lotus Notes..... which have rich features / equivalent almost like OL. Search on the net and u will get lots of info on the same with configure, installation, uses, requirements and more !

Evolution or thunderbird might work for you

Well, that's the "beauty" of the closed source software if they use "tied up" approach. Eventually people will realize that's not acceptable... I'm losing myself here, you get my point though ;)

@sysman in my opinion there are no client on Mac, Linux or BSD which beats Outlook do to there exchange implementation.
But I will say Thunderbird has come a long way, I would say. What is it you are missing in Thunderbird?