Really, this is something you could find if you spent just a couple of minutes looking.

If you have an NTSC PS2, then yes a NTSC game can work for the "swap trick". If you have a PAL PS2, then you'll have to use a PAL game.

It seems pretty obvious that you'd use what ever kind of game is native to the console you're trying to fool during the boot phase.

There are videos that show how to do it if you're having trouble. Just look at Youtube or a similar site.