Instructions apply to default location of FS9 and FSX in Windows XP only. The location in other operating systems may differ. 

Copy and paste the six .PLN files within this folder to...

FS9 - C:\user\My Documents\Flight Simulator Files.

FSX - C:\user\My Documents\Flight Simulator X Files.

To load .PLN files...
In FS9 or FSX select Flights\Flight Planner - Click on Load...
If the 'look in' box doesn't display 'Flight Simulator Files' or 'Flight Simulator X Files'. browse to the location as detailed above.

Highlight the flight you wish to fly and click on it.

The FLIGHT PLANNER dialog box will display the departure and destination airport details plus other options where the flight can be modified if desired.
Click 'NavLog' to view the flight details. I recommend you use the print option. Click 'OK'.
Click 'OK' again. A dialog box will open offering a choice of whether or not you wish to move your aircraft to the departure airport.
Click 'Yes' or 'No' and you will return to the flight simulator with the flight loaded.

Enjoy the flights.