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?

Check this out:

Maybe he can tell you where he got his database.

This app lets you type in a zip code and as you do so, a map of the US zooms in to the portion pertaining to the zip. So, if you type "9" it highlights the west coast. Then "4" and it drives down to the bay area. Etc.