Yes they are region free. I bought MGS4 and Burnout from the US and they work fine the only downside is the DLC is region locked(SA psn DLC for Burnout did not work) and sometimes the multiplayer is region locked(like MGS4).
As far as i know most blu-ray discs include or atleast state they are region locked... But as far as i know blu-ray roms can read any region this goes for the PS3 aswell. Maybe there was a software change, but i have used alot of imported games and movies that i borrowed on my console and they seem to work absolutely fine.
what i would like to know is that... does the PS3 disks work the same way as normal DvD's because I know i have had alot of problems in the past when it comes to changing regions on ur dvd player everytime