Multiposting (Open Source / not developed any further)
Multiposting lets you post on multiple facebook groups at once.
NOTE: This code is currently not working out of the box. Since Facebook changed their API it is not possible to post in groups via API. You can use this code as basis for your own implementation.
Due to lack of time this code is not developed any further.
Information: http://www.herr-yeah.de/open-source-auf-mehrere-facebook-seiten-und-gruppen-auf-einmal-posten-678 (in German)
License: CC BY-SA 4.0