Sync Mate is a utility for Mac OS X that allows you to synchronise your Windows Mobile 5 or 6 device with your Mac.

The free version of the software is available for download here:

http://www.eltima.com/products/syncmate/

The free version allows you to synchronise contacts and calendar with the Mac Address Book and iCal applications, as well as read your SMS messages.

The Expert verison, which you need to purchase, allows you sync  awhole lot more, as you can see from the screenshot above. But the real benefit of the free version of the software is that when the PDA is connected to the Mac for the first time, a network adapter is installed within the System Preferences, which allows you to use your Mac's Internet connection from the Windows Mobile device:

The other really cool feature, which to the best of my knowledge is unique, you can also mount the Windows Mobile PDA as a drive, to view the contents of the device and drag and drop files to and from the Mac. Once mounted, the PDA is displayed as a drive:

Which can be controlled via the Finder:

Eltima supports both USB and WiFi connections.