From the FAQ: http://support.na.square-enix.com/fa...67470&ret=main

Can I use the same character on both the PS3 and PC versions?

Yes, by selecting the same service account when activating the PS3 and Windows versions for the first time, it is possible to play the same characters on both the PS3 and Windows versions.
(If you own Version 1.0, select the Version 1.0 service account when activating the PS3 version for the first time.)

*It is not possible to simultaneously play with the same service account on the PS3 and Windows version, so please beware.
*You will need to purchase both the Windows and PS3 versions of the product.

Selected service accounts cannot be changed later, so please register them carefully.