The software is only for the PocketPC. The GPS will work with any Bluetooth enabled device, including the P800, but without the software it's kinda useless.
Here's their response to the question...
Dear Stephen,
Thanks for your mail.
Currently, we are investigating the options to release software like City Maps and Route Planner for SYMBIAN 7.0 based phones like Sony/Ericsson P800 and Nokia 7950
However, we can not give you any date when to expect a release.
