The July 2013 issue of Corocoro revealed that a special Jirachi event distribution will take place in Japan from July 1st, 2013 until July 31st, 2013 for the players of Black, White, Black 2 and White 2. The official website has revealed the details and it will coincide with the airing of the anime episode
Wish Upon Jirachi! The Seven Days Miracle! (ジラーチに願いを! 七日間の奇跡!!).
Source:
http://www.pokemon.co.jp/info/2013/06/130615_g01.html