The price and release date for Pokémon Mystery Dungeon: Magnagate and the Infinite Labyrinth (ポケモン不思議のダンジョン　～マグナゲートと∞迷宮～) was announced on the official website earlier today. The game will be released on November 23rd, 2012 and it will retail in Japan for 4800yen. The digital download version will also be available off the Japanese Nintendo 3DS eShop for 4800yen. The cover for the game was also revealed and it has the Nintendo Network logo on it which indicates the game will have some features that support the new online network.

Source: http://www.pokemon.co.jp/ex/dungeon_magnagate/product/