question
 

i have one question...can we talk about emulators?the whole " how can we play ps2 games in pc(having them of course).is this illegal?

You can talk about emulators, but there aren't any fully working ps2 emulators.

ok thanx man
i have pcsx.can't it play ps2 games?(orignal and not)
haven't got anyyet so haven't actualy try

No, hence Bighap telling you that there aren't any actual working PS2 emulators...

There are currently three promising ps2 emulators. PCSX2 ( as u already mentioned), PS2Emu and NSX2. All of them are making rapid progress but even with the best you are still very lucky if the thing will get you to the title screen of the game you are trying to boot even on the simplest games.

The emulators, as well as relying on people coding them in there own time also rely on leaps in PC speed and gfx technology to ensure that yr home computer will be able to play games as a ps2 would so were not gonna see the ps2 equivalent of AdriPSX for at least another year.