Burmecianblue
ShinRa Guard
I'm pretty sure you can play prior console games on the PS3. In fact, I did so not only 2 hours ago on my room mates PS3.
I have heard that some PS2 games aren't compatible and that all PS1 games are but don't quote me on that.
I have played FFX on my PS3 for example.
Depends on the model. The very early 60gb PS3's can play all ps1 and 2 games because it has the hardware. I've heard a few rumors about a PS2 emulator for the PS3 but I wouldn't hold my breath.