They've already published/announced eight games for DS, and have just announced their ninth, Heroes of Mana DS. It's also looking like a FFXII spinoff game is in the works as well.
edit, well i was checking out some scans of a japanese magazine, apperent squares releasing 2 new games for the ds, a ff12 spinoff and a sequal to kingdom hearts:com.
Oops. Looks like S-E revealed ANOTHER DS game. This one is called It's a Wonderful World and is by the Kingdom Hearts team. ^^