Your best bet is to purchase a PS2 specific to whatever country you want to play games with. For example if you want to play a Japanese game, then you should get a Japanese PS2. Otherwise you can mod it with a chip, but this requires opening up your PS2 and messing around with its insides.
i have a proble with PS2 i doesnt play games from other countries =/ ... do i have to unlock it , and how??