Thank you both hijinks21 & Chairboy:
The postal code is very good, but applicable to North America only. Your ideas made me dig a bit deeper into MapPoint programming & I think the "GetLocation" method is probably more universal using the coordinates:
http://msdn.microsoft.com/library/de...etLocation.asp
Just still wonder if there's already solutions, since I don't want to "reinvent the wheels" ... (-:
By the way, I heard that NavTech has already been testing their own data with weather info linked into in-car GPS systems since last year, so "In-car Weather Info System" will eventually be a popular standard in conjunction with the GPS.