FS2004/02/00. Complete with a color map to track all your moves in a separate window.
Can be used with or without Flight Simulator running.
Allows you to use all the planes in your hangar, control the weather and much more.
Can also print a simple map to help you.
Comes complete with the default FS database with all the airports, VOR, ILS, and airways, but, you can build your own database.
Extensive document as well as an SDK in C++/VB.