Also if it's a NTSC disc, a PAL PS3 will not play it, even if it's region free. I tried to play a regional PAL disc in my NTSC console and it said this format not allowed.
Some blu-rays are region-locked and others are not. I don't know how you can find this out. A friend of mine has a U.S console in Europe and he managed to watch surf's up PAL so that means that this title is region free.