There was another thread that discussed going from GW to iCal.
If you use Mail.app, and connect to GroupWise via IMAP (vs POP), you'll see a calendar folder. You can open any of those messages, they are your calendar appointments) and then double click on the attached .ics file to add it to iCal.
Unfortunately, going from iCal to GW is next to impossible. So, if you enter an appointment on your Palm or BlackBerry and sync it with your Mac, you can forget about it getting into GW. It's quicker, easier and faste to re-type the event.
The problem, in this case, isn't with Apple.
GroupWise does not conform to the .ics calendaring standard, instead using some type of variant. No matter how I have tried to import my iCal data, GroupWise (both v.6 and v.7) ignore the timezone settings, or the lack of timezone setting, and then shift the event either 7 or 8 hours, depending on daylight savings being in effect or not in effect.
Having studied the .ics specification to attempt to form a resolution to this problem, the only thing I've come up with is writing an Apple script or Automator action to go through an exported .ics file and then change the times by +8 or +7 hours prior to importing into GroupWise.
Aside from being a pain in the rear to do this, it also requires using the Windows version of the GroupWise client, since you can't import (actually 'retrieve' a file from either the Web client or the cross-platform Java client. In my case, I'm able to log in to Citrix to use the Windows version, so I don't have to get to an actual XP machine. I'm sure this solution isn't readily available to most.
From what my colleagues tell me, syncing the GroupWise calendar with a Palm on a Windows machine must be done with a third-party application called IntelliSync. It's not much fun on the Windows side, but it guess it's technically better.
Syncing between GroupWise and BlackBerry appears to require the purchase and installation of the BlackBerry Enterprise Server, something we're not going to do here. So apparently, nobody with a BlackBerry can sync their calendars.

I am using the Mail app to connect to my GroupWise mailbox via IMAP and have one serious issue/complaint. When I use a native GroupWise client-- on Windows or the lame one for the Mac-- copies of sent messages are written into the 'Sent Items' folder. When I send a message from the Mail app, however, copies of sent messages are written into the 'Sent Messages' folder. Besides for being a nuisance in that another top-level IMAP folder is created in my mailbox, the problem is that messages that are sent from the Mail app are not considered 'sent' from GroupWise's perspective, presumably since they do not show up in the Sent Items folder.
I do not have problems with other IMAP mail clients, such as Thunderbird, as they are configurable as to which folder to use for the sent items. Mail is not quite as flexible.. rather than selecting where to store sent items (or junk or trash) on the server, it just has a toggle as to whether to store it on the server or not.
Is there any way to fix/work around this? I would be much more inclined to use the Mail app were I to know that my sent mail was being properly accounted for.
Thanks,
- GC