Hi to you! I briefly toyed with the idea, this is what I found out...
Microsoft Autoroute will accept a GPS signal, but basically all it will do is show a dot on the map, and rotate / move the map around the dot... No navigation features as such.
However, take a look here:
www.66.com
These folks provide a range of solutions- I opted for the GSM / Satnav solution for Nokia, as I don't have a daily use for GPS. It does exactly what it says on the tin, to my complete satisfaction. Check their versions for PDAs and laptops (I think...).
Hope this helps!
Maxbert