Shiny Palkia, Dialga and Giratina will soon be available to download from EB Games stores in Australia and JB Hi-Fi stores in New Zealand. Each member of the Sinnoh creation trio will be available for two weeks beginning August 30, and can be downloaded to Black, White, Black 2 and White 2 games.
Shiny Dialga: Friday August 30th, 2013 – Thursday September 12th, 2013
Shiny Palkia: Friday September 13th, 2013 – Thursday September 26th, 2013
Shiny Giratina: Friday September 27th, 2013 – Friday October 11th 2013
In order to receive the Pokemon you must have the Pokedex and no more than 11 Wonder Cards. Simply go to a participating store, start up your game and select Mystery Gift on the title screen, followed by Receive Gift and Get via Wireless. For a list of participating stores, click here.
Source: Nintendo Australia