For all people out there how have a jailbroken iDevice, I found a new app on Cydia called FMC Planner. This app lets you plan a flight according to the different sections of a FMC. The app also has Dropbox support.
The app works on all devices running iOS 5.0 or higher.
A valid copy of PMDG's 737 NGX for FSX is needed, cause the apps data is based on the -600,-700,-800 and -900 model of PMDG.