1. fly to the galactic building in veilstone.
2.you will see a galactic grunt.
3. talk to him and he will run a way like a chicken and leave the key behind in a pok-ball.
4. get the the pokeball and you will receive it.
5.go get him and punch him in the face[just kidding]
hope i help
u can find him in the galactic building in veilstone (p.s its not the galactic ware house
you go to the team galactic ware house
its in the galactic ware house in velistone
simple answer go to Veilstone city and at the top right corner there is a team galactic building and in front of it there is a team galactic grunt talk to him and he drops the ware house key but here is a catch it breaks in the key hole after you use it and there is more doors so you have to find the galactic key... oh ya and one more thing the galactic key always works!
Talk to the Galactic Grunt by the satilite and he will drop something. Pick it up and it opens every door.
after getting your 7th badge go to veilstone city go to the galactic grunt and he will drop the key
the galactic key is in the veilstone city ware house
the glantic ware house is in velistone city.but i think you need a key.
in the galactica ware house to the left of the galactica base NO NO YOUR A LIER
in Pokemon platinum you get it in the team galactic ware house looker will open it up and it will be on the side
you can get dusk stones in the galactic ware house,victory road or using a Pokemon with the pick up ability
You get it in heart home city's Team Galtix ware house