Kingdom Hearts: 358/2 Days for Nintendo DS appears to star Roxas from Kingdom Hearts II, but its main draw looks to be four-player simultaneous play using members of Organization XIII. It will be in full 3D.
Oooooh! Sounds intriguing. I know four people who are willing to play it as well. XD
Kingdom Hearts: Birth by Sleep for PSP looks to be a single-player adventure in the vein of the PlayStation 2 iterations, though not "Kingdom Hearts III." Birth by Sleep's protagonist was not explicitly named in the presentation, but he looked an awful lot like Zack of Final Fantasy VII/Crisis Core fame.
Dammit! *sighs* I guess I'll be buying a PSP soon. :/
I don't think the mobile game will be released in the USA or Europe. Square hasn't released their other cellphone games to other countries.