Flight plan generator

`Does anybody know the syntax of the line entries in the .pln text files produced by the flight plan wizard in FS9? I wold like to be able to generate a loop or similar such route suitable for a flying tour bus. Ideally if I knew the lat/long of the spots I wanted to fly to I'd like to be able to write the lines in a format that a GPS could read.If there is an add-on that already does that, please vector me to it.Thanks in advance,Bill