I have written a program called bearing which you might find of interest.
ftp://ftp.mindsprin    g.com/users/n8kl/bearing.zip
Here is part of bearing.doc explaining the program:
Bearing.exe is a DOS program which calculates the bearing and distance
between
two locations. The program contains an internal database of 1200 U.S. cities
and about 300 cities throughout the rest of the world.
The data for each city includes the three-letter airport designation,
latitude
and longitude of the airport, and state or country code. (Country codes are
listed at the end of this file.)

When bearing is run without arguments you are prompted for a starting
location
and then a destination location.  Both locations may be specified in many
ways.
1. You can enter the three-character airport designator.
2. You can enter the actual name of the city and state as in "lansing, mi".
  Case and spacing don't matter.
3. You can enter the city without a state.  If there is more than one entry
  for that city because of multiple airports or states, you are prompted
  with each matching city, state, and airport so the correct one can be
chosen.
4. You can enter a state abbreviation. You are prompted with each city and
  airport.
5. You can enter the actual latitude and longitude.  Examples of valid
entries
  are: 37n25w 14s15w 37.30n85.45w 52.4n12E
  Invalid entries are: 37.8n16.4w because fractional degrees must be in
  minutes which must be less than .6. Note that if the -. option is used
  (described later) degrees are input as a decimal number.
6. You can enter the grid square.  Grid squares are used in Amateur Radio to
  give the approximate latitude and longitude of a station.  They are either
  4 or 6 characters long.  If a valid grid is entered, the database is
examined
  and the closest city is displayed along with the approximate distance to
that
  location.

88's N8KL