As mentioned in a previous article, Jun'ichi Masuda recently revealed that a brand new Pokémon game would be released by the end of the year in Japan.  Some speculation has been made as to whether this will be a title for the DS, or possibly a successor to the DS; previous generations always began on newer handhelds.

Nintendo is evidently working on new hardware, according to game producer and designer Shigeru Miyamoto.  He wouldn't say what kind of hardware it is, but if it is a brand new iteration of the DS, then it stands to reason that the new Pokémon game would be released on this hardware.

Bear in mind, of course, that this is just speculation.  Be sure to check back at Project Pokémon for updates as they appear!

Source: Shigeru Miyamoto Discusses New Nintendo Hardware (1Up)