Im thinking of writing( or attempting to write ) a routing program for delivery trucks. I was wondering what the best way to go about this would be? I would like to use zipcodes, but I would also need that lattitude and longitude to be able route them in some kind of ascending or descending order. I was also thinking that maybe I could somehow come up with a DLL ( if that's what I needed...not sure ) to maybe hook into the CDROM that comes with the thomas brother map books( you know the one in the back that you get when you buy the map book ) That could possibly read the map and or grids to route them the most effeciently.( Is that legal ? )

Any thought on how to procede would be appreciated. Aslo do you know where one might get lattitude and longitude for zipcodes for free?