Ты can't actually get Kingdom Hearts/Kingdom Hearts II for other than PlayStation 2, but Ты can get a program for your PC called "pcsx2" или other similar programs, and with a little work and a gamepad for your PC Ты can play Playstation1&2 games on it! Ты can download the program here;
link Here's the official English guide to using it;
link Ты can get help from this forum;
link The gamepads cost quite a bit, so if Ты want Ты can program your keyboard to work like one, but it's quite difficult to do and difficult to play with.
A new game called "Kingdom Hearts: Birth by Sleep" is coming out on PSP, so if Ты don't want to buy a PS2 или go through the PC-to-PS2-way, Ты can just wait for that I guess.
I hope this helps! :]