Impatient fighting game fans will want to pass up on importing the upcoming Arc System Works fighter based on the Persona franchise. An Atlus employee confirmed the rumor that Persona 4 Arena will be the first PS3 game to be region-locked. Atlus has not yet divulged a reason for the lock, but they expect to have an official response sometime in the future. Looks like our friends in Europe are going to have to wait awhile to get their hands on this game.
For those who don’t know, unlike the Xbox 360 where most games are locked to regions, all Playstation 3 games up until this point have worked on any system in any country. It is entirely possible to import a game from Japan and play it on a PS3 bought in the United States. Hopefully this is an isolated incident and whatever problems they ran into do not surface in other games.
Source: Atlus Official Forum