When it gets back up, register there and it will ask for the game code
the code is found on the black/white load screen(of course you will need your C-Gear)
In your C-gear in the game itself hit the Wifi section and the Game sync will be there,
sync up and the pokemon you choose will go to sleep
Tho right now since the Global link is down, you can't do it as of yet, site says it will be down up to 10 days(so about till the end of the month)
In the dream world you can grow berries(which can be used to purchase things for your house
go to Dream island, where you can get items and meet pokemon not in Black/White, and after awhile can bring them from the dream world to the game
The Pokemon doesn't wake up until you press the wake up button in the browser, and you can only access Dream world once a day
Cant test any of this because the server is down, but after if anything doesn't work let me know
after your pokemon wakes up and you need to get the pokemon that came back or times, hit the Wireless on your
C-gear and hit the left one to enter Hilink and you will be sent to your world
which is in the center of the map, there you can get items and catch the pokemon from the dream world
