hi i have a question how and with witch programmm can i plan a flight for pmdg 737 600-800

pen and paper come to mind (and do indeed work well if you have charts for the area you're flying in) :)FSBuild 2 has excellent capabilities, I use it all the time.

FSNavigator is another possibility, this has an export module which can create flightplans for both the PMDG Flight Management Computer and the Flight Simulator flight planner: that way ATC and the FMC are working off the same route - at least until it comes to your approach to landing, when Flight Simulator can't handle STAR's.