I've been working through a project for a KG client that involves running through the same script on Windows (XP), Mac OS X (10.5) and Linux (SUSE Linux Enterprise Desktop). I mentioned the overall parameters of that effort in the post Off Topic: Desktop evaluation - Linux, Mac OS and Windows. The project is going well and I've gotten all three platforms to do nearly everything on the list.
After getting the systems to work with a standard file server, network printer and share office document, my one remaining challenge was integrating Windows Mobile 6-based devices with all of the desktop challengers.
As one would expect, it was very easy to install the newest version of ActiveSync on Windows and get the Windows Mobile device to fully synchronize calendar entries, contact lists, tasks and notes with the desktop system. Synchronizing both the Mac OS X-based system and the Linux system haven't gone quite as well. This is due to the fact that the only sychronization method the Windows Mobile devices appear to understand out of the box is Microsoft's own ActiveSync and ActiveSync is only available on Windows.
I found several alternatives for the Mac OS-based systems including Eltima's SyncMate, PocketMac's cleverly named product, PocketMac, and Mark/space's Missing Sync for Windows Mobile. I downloaded and installed all three of these products. None of them would fully synchronize the two systems. All three of them hung somewhere during the synchronization process and had to be forced to stop.
I was able to find software that would synchronize the Windows Mobile Calendar with Google Calendar and a way to synchronize iCAL on the Mac with Google's calendar. While not very pretty, it worked. Synchronizing the contact list in some automated way still eludes me. I worked out a manual process using Gmail's contact list but, it's not very pretty.
I'm still working through the task of synchronizing the Windows Mobile device with Linux and don't have much yet to say. I have, by the way, made Evolution synchronize with Google's calendar and have used the same ugly process to move the contact last from Gmail into Evolution.
This has been a valuable learning process for me. Even though I've been working with all three of these operating systems for years at some level, this project is forcing me to do things that I've never bothered to address until now.