Novell has released a Service Pack to the 1.0 version of GroupWise PDA Connect. Based on some initial tests, this version seems to work well for synchronizing the new Windows Smartphone devices with GroupWise.
I should clarify that Microsoft has two different versions of their mobile OS. The version that runs on Pocket PC devices (i.e. like the new hp iPaq phones) is supported by GW PDA Connect. The version that runs on non-PDA cell phones is not supported (i.e. like the Motorola MPx 200 series).
One slight curve ball comes during installation. You get an option which mobile OS to select (Palm OS, Pocket PC, and Pocket PC 2003). Even though the iPaq runs the 2003 version, when I chose this option, the software did not install correctly on the handheld. When I tried just Pocket PC, it worked fine.
GW PDA Connect is a free download from Novell and works far better than any of the third party GW sync solutions that I've tried (Intellisync and Nexis).
The latest Hotsync Manager for Palm devices and ActiveSync for Pocket PC devices must be installed on the host computer to provide the conduits to the PDA before installing GW PDA Sync.