Latitude Maps

What is the formula for converting latitude and longitude from two points to bearings?

I have location A) latitude/longitude and location B) latitude/longitude. I need know know what the bearings are for location B relative to location A. Can anyone point me to a reference? The lat and long are in decimal degrees.

Public Comments

1. that requires a whole theory...basically you have to determine that great circle which contains those two locations...then the tangent in one of them makes an angle with the local meridian, of which measure is the bearing you are looking for...
2. Search under "Aviation formulary."