that hapen to me a few times, like i see we dont have a hd tv.that happen because some pal game dont suport 480p, suport 560p and 720p , one solution is open the PS3SFOEdit and load the param sfo from the game, in the window of resolutions you will see the 480p resolution is disabled. make a click the will be active and save. that work for me in games like apache air assault (pal) gundam (pal) and other games i dont remember the only game that not work with this way was hokuto musou (pal).
PS3 games are region free but you must have a standart hdtv to all games work.
Sorry for my english i speak argentinian.