An upcoming issue of the Official PlayStation Magazine says that Square Enix is planning to reveal a new action game sometime in April. Other than a single screenshot (which we regrettably do not have available), there is very little other information on which to go.

The screen shows a man with long white hair dressed in black. He has a blue scarf around his waist and is said to carry a giant sword. Sephiroth perhaps? Probably not, as then it would have been quite obvious what the game was connected to. -- Final Fantasy Union

They add that the format (by which I'm assuming they mean PS3, PSP, or PSN) has not yet been revealed, but will hopefully come to light when the announcement comes. Then again, these days it seems like too much to ask what platforms a game will be available on, so we'll just have to wait and see.