I would like to update this thread to others that are still interested.
I have received my Leadtek 9537 Bluetooth GPS unit and HP Bluetooth Headphone and they BOTH work at the same time with my iPAQ 2210 Pocket PC PDA (ROM v1.10).
When the road noise gets too loud (i.e. highway/motorway), I can use the bluetooth headphone for better listening to the voice from the PDA.
However, its more of a gimmick as on long road trips, without voice feeds from the PDA, the headphone switches off after several minutes with its built in powersave feature negating its use
But if you want to listen to MP3s or audiobooks and don't require the voice prompts from the GPS, the headphone will still work very well
Lastly, the AC adaptor that came with my Leadtek GPS and the HP Headphone is 100% compatible to the iPAQ Pocket PC PDA! Not only that - their adaptors come with interchangable heads for international travel! This is all a surprise bonus to me! :devilboy: