Nintendo & Y during its webcast. The trailer announced that the games will premiere worldwide on October 12th. The trailer also showcased new features of the games, such as feeding and using a stylus to pet Pokémon. It also reveals new Fairy-type Pokémon, including familiars, and new Pokémon: Jigglypuff, Gardevoir, Sylveon, and Marill. The game will be released for Nintendo 3DS.
Check out the trailer: