Nintendo has announced that they will release the newest Pocket Monsters (Pokémon in the U.S.) title, Pocket Monsters Crystal, for Game Boy Color in Japan on December 14, less than a week after the releases of Dragon Quest III for that system and Square's Final Fantasy for WonderSwan Color. The game was previously known as Pokémon X.
A trickle of background information for the game has been released, as well. Pocket Monsters Crystal takes place one year after Pokémon Gold / Silver, and introduces a female character who travels along with the main character throughout the game. Pocket Monsters Crystal makes use of the Mobile Adapter GB to allow players to battle or exchange Pokémon over cellular phone connections.
It is still uncertain when the game will be released in North America, or whether the Mobile Adapter GB will be released here. RPGamer will keep you updated as more information is received.