Something that we seemed to have missed at Nokia World (even our one-to-one walkthrough of the extra software never covered this) is the Contacts Transfer app, available to Nokia Lumia owners. The app will allow users to pair their existing Symbian handset to the Windows Phone and transfer contacts across via Bluetooth. These contacts will then be synchronised with the Live ID associated with the phone.
The functionality appears to be limited to contact data and will only work one-way. Once the app has been launched, it will search for local Bluetooth devices, and once the correct device is selected a pairing request will be sent to the Symbian handset. Couldn't be simpler to upgrade to Windows Phone.