1UP reports that these will be three entirely different titles, although all three will share the theme of "time." Kingdom Hearts: Birth By Sleep will be headed for the PlayStation Portable as a single-player action-RPG romp in the same vein as its PS2 brethren. Kingdom Hearts: 358/2 Days for the Nintendo DS is a full-3D game starring Roxas from KHII, and featuring simultaneous four-way multiplayer.
The final title, Kingdom Hearts: Coded, is being developed for mobile phones, and features the original Kingdom Hearts cast in a story that appears to take place in between the first and second PS2 games.
Sony PlayStation Portable PSP-2000