To add Munich to your database
Munich does not cooperate with Google Transit beyond Google Maps layer data (no routing) and therefore probably does not have the necessary GTFS data available. Sadly German transit agencies are most often locked in with external routing software providers who have no interest in publishing their data – even if this would greatly benefit their customers.
Please make a request to the MVV here: http://www.mvv-muenchen.de/de/home/meta-navigation/anregungen/index.html
and ask them to make their data available for free as GTFS.
I'm happy to add Munich. However, just because Munich gave the data to Google does not mean it's publicly available. Please ask the MVV to release their data to everyone.
Peter Sonntag commented
In the meantime Munich has been added to Google Transit. Are you still working on the project? It is definitely great and helpful.
I just made such a request for Munich. Danke Stefan für diesen super Service!