Just to clear up any confusion, recently a lot of people have mistaken a statement on the development cycle of Final Fantasy XIII as "FFXIII for PC".
Square-Enix have stated that Final Fantasy XIII will be developed using Crystal Tools on a PC for Playstation 3, then Xbox 360. This comment was mistaken as "Final Fantasy XIII is being developed for PC."
Square Enix have recently said that they have no such plans to release Final Fantasy XIII for PC after being contacted by VG247.