Square Enix have released the official details of Final Fantasy XIV: A Realm Reborn's launch plans in Europe. You can pre-order the Collector's Edition of the game starting today and if you pre-order you have early access (from April 11) with the game launching on April 14. The beta will start on February 22 and all PS4 owners are invited to join. For those playing on PlayStation 3 you will be able to transfer over to PS4 at no extra charge (however, once you transfer you will only be able to play on PS4).
Pro tip: Final Fantasy XIV: A Realm Reborn (PS3) is on sale in the PlayStation Store currently so you could just get that version, play a bit, and then jump on the PS4 version when it launches.