Official Goblin Trailer:
This video is very entertaining and gives you all the information behind how the Kazan goblins came to be on Azeroth and why they begin there journey as members of the Horde! Lok'tar Ogar! Victory or Death!
Fan Made Trailer:
This is not the official release nor the official story line, still a very well created and entertaining video. The reason I posted this was to keep the fan-boy worgen lovers at bay until the official worgen cinematic is released.
Enjoy!