Wow, that's not too far away now. The Japanese version will be on trial come mid-January with a release date pencilled in for the end of February. The game is free to play, or there will be a special boxed version retailing for 5,220 yen with bonus armour, characters and other content.
A western version is confirmed, hopefully it won't take as long as some to make it over here. Particularly with PC, iOS and Android versions also on the way, which should give it a high priority for translation. The Vita and PC versions will share servers and be cross-compatible.