It's the JP servers, so you might want to find the guide on pso-world since you'll be registering and DLing on the JP site lol.
A decent computer but it doesn't need to be top notch or anything.
Just a note, since it's on the JP server it's all in japanese. However there is an english patch that people have created that translates most things in-game, like quest objectives, the menu, NPCs, etc. Doesn't do item names though. You can just look at a guide for that. Still a fun game
I'm playing as a Force on Ship 7.