Having just read a "guide" here on ebay saying not to buy cheap inported NTSC games for the PS3, I feel obliged to educate people as to why the games appear in black and white, etc, on your television.
By all means, if you own a PAL PS3, buy cheaper, imported NTSC games. The PS3 IS REGION FREE FOR GAMES (not for movies however, so don't buy NTSC blu-ray discs!). It is a deliberate move by Sony to try to undermine those gamers and modders who chip their consoles to play imported games, which cause Sony to lose a lot of money through illegal trades. So NTSC games will work on your PAL PS3. The only reason some people believe this to be untrue is because their TELEVISIONS DO NOT SUPPORT NTSC VIDEO FEED. In the UK, tvs are PAL as standard (I-PAL). Many newer tvs also support NTSC streams, and so the games will appear exactly as the PAL equivalent on these tvs. However, some older (but possibly some new ones, it all depends on your tv!) don't support NTSC, and so the picture appears black and white, or there are can be other associated problems.
If you check out your TV manual before purchasing games, you'll know whether it is suitable to buy NTSC games in your case. It is not the PS3, nor Sony who is at fault for the NTSC problems, it is simply that people have incorrect tv equipment. A quick look at any one of the hundreds of technical websites will tell you that the PS3 is region free, if you still don't believe me.
Don't fork out over the odds because other people have lower quality televisions and would believe it's the fault of their playstation - this information could save you a fortune as NTSC games are much cheaper!