The games won't work you have to get the PS2 chipped. My husband chipped our PS1 and has been waiting for the warranty to run out on the PS2 before chipping it. I believe its not quite as straight forward as chipping the PS1 though. The chip required is called Messiah, thats the main one, apparently there is another one available but from a lesser known or unknown company. I believe it cost around £30 but it can cost £90 to get it done. Unless of course you know a friendly Electronics Engineer. The information is out there on the net. A site called RegionFreeDVD.net can point you in the direction of making the PS2 region free for DVD's if you have one of the first PS2's. Not sure about later versions.
Kazd