Nintendo has revealed that they're developing Pokémon Black and White 2, which will serve as direct sequels to the DS games which released towards the start of 2011 in Europe and North America.
This is the first time Nintendo has produced directly named sequels in the history of the franchise, with games typically evolving into new incarnations.
The games are also being developed for the Nintendo DS, not the Nintendo 3DS and are scheduled to release in June 2012 in Japan. At present, no release has been mentioned for North America and Europe, although it typically happens a few months down the line due to localisation.
Two new legendary monsters will feature in the sequels: Black Kyurem and White Kyurem. They will supplement a rather expanded range of Pokémon.