I did not know that it was, but in case you discover that it is not, I would advise you to get a disc called DVD Region x, which also let you choose your own region. The disc says you need a memory card in order to use, but that is only if the basic disc does not do the trick, in my case it worked wonderfully, but then again I have only used it once, on one disc...
Oh... I did not know that Another advice though would be that there actually is a gaming hardware forum here as well, I bet regulars in that forum would know more, at least about the Gameshark
I was able to set-up my PS2 to play region2 DVD's without any aditional hardware/software. But It can't convert PAL...so only NTSC region 2 (Japan).
Now I need a list of better versions in region 2.
Only Takeshi Kintano's Brother comes to mind.