Fatal Inertia EX is already out in Japan and there's also a demo available on the Japanese PSN (which just so happens to be completely in English). We advise you to check the demo out if you're interested in this title -- well, only after you watch this new trailer for the game.
As for the North American release date, as far as we know, the game was supposed to come out late last month. That obviously hasn't happened. Perhaps we'll be seeing it soon.