GIS Help: distance calculation based on ZIP Code

Thank you very much, I will look into it.

If it really is only 200 then I'd start typing them into Google's
direction finder and typing in the distance/time given. Even if you
only do one per minute they'll all be done in half a day easily. Job
done.

 If it is going to be 20,000 then you either need a small army or some
way of automating the process. I could give you my python code that
scripted the process to both Google's Routing and an OpenStreetMap
routing service (made for some interesting comparisons), but I just
tried them again and they are both broken - probably because you're
not supposed to script these things anyway.

 Small armies are available for hire via Amazon's "Mechanical Turk"
service. Or find some grad students willing to do it for food.

Barry