sequel

Set two years after Pokémon Black and White, Black and White 2 features a Pokédex with about three hundred Pocket Monsters. The game begins in a new location called Hougi City. It's still located in Unova. The game will follow two new trainers, with a new rival and new gyms.

Pokémon Black and White 2 is slated for a June release in Japan. It will be out this fall in the West.

The difference between 'gray' and 'grey' is pretty subjective, though I personally prefer 'grey.'

Pokéstar Studios!

Pokémon Black and White 2 are the first Pokémon games to be direct sequels instead of a third "expansion" game. Pokémon Black 2 and Pokémon White 2 are slated for release in June on the Nintendo DS in Japan.

Update: Pokémon Black and White 2 will be hitting North America and Europe this fall.

Source: Joystiq

While the games are out in Japan this weekend, they'll be out in America sometime this Fall.