The teaser site we posted a few days ago has been revealed to be a new, upcoming Final Fantasy game for the DS, Final Fantasy Gaiden: The Four Warriors of Light.
Unlike the DS games to date, this is neither a remake nor a spin-off. Instead, it's a entirely new story made for the touch screen controls. While there is the menu-and-turn-based battle system we have so much nostalgia for, Jump magazine is excitedly calling it a new battle system. There is no MP. Instead, each character has a meter above their head with a number of yellow dots, probably representing AP. Each action costs a number of AP. In order to get more AP, there is the "Charge" option.
There is also some equipment customization revealed in the scans. Like some of the DS remakes (I'm thinking FF3 here) , you can change the outward appearance of your character. However, in this game, they take it a step further. Different equipment changed in the menu will be visible on the character.
Finally, the "4" on the teaser site is explained. While there's only two characters on the back of the dragon right now, there will be four warriors of light revealed.