WM Soft have released a freeware application called Export Contacts which will create a HTML or XML file with more than 50 properties, including photos and ringtones. Although your contact details are effectively backed up when you synchronise, this free product will let you create a further backup store.
WM Soft plan to add an importing feature in a future version, however you can download it now here. This software requires .NET Compact Framework 2 to be installed.
Link – Export Contacts