I always find it amusing how everyone always just assumes the PS3 is region free for games. I certainly wouldn't count on it.
This is based upon two things:
1. Sony have said they are not region locking their games.
2. JAP and USA are the same region for Blueray movies.
Did you know that Microsoft also do not region lock their 360 games. Nearly all MS published titles are region free. However, the disks have the capability to be region locked and nearly all 3rd party publishes do region lock the games.
Because Sony chose not to region lock titles they publish, doesn't mean the console is region free for games. I wouldn't be very surprised if the majority of PAL games will not work on NTSC consoles. Also, I would also be surprised if Sony keep their word, since they have lied about everything else.
I also think point 2 is a reason for confusion. In the days of the DVD, USA was region 1 and JAP was region 2. In the Blueray world they are the same region, but Europe is a different region.
I honestly can't see most 3rd party publishes creating region free games knowing that users could import a release from the states for £30 or pay £60 for the same release in the UK. It would make no commercial sense.
I'm not that interested in the PS3 until it gets some good exclusives. Till then i'll stick with my 360's.