You can also try "DavMail Gateway":
I've been using this quite successfully with Thunderbird (with the Lightening plug-in).
This combination doesn't have all of the features of Exchange + Outlook, but it comes very close. I haven't tried using Exchange folders, but instead I can sort and store the mail on my workstation, which I prefer. With the lightening plugin for Thunderbird, I can see the Exchange calendar, acknowledge meeting requests, and set up meetings, including inviting other people with accounts on the exchange server. I can't open a calendar belonging to someone else (which I can when using MS Outlook), but when creating a new meeting I can view whether someone else is free or busy at a specific time.
The current x86_64 version of DavMail works well with Slackware64 13.37 and Slackware64 current. I haven't tried the 32bit version.