can ps1 and ps2 games be played on the ps3?
It depends on the version of the PS3 you have. The new slim ones are NOT backwards compatible. The first generation had hardware emulation for PS2 games, and would play 99% of them. The second generation had software emulation that didn't work as well and was only compatible with about 3/4 of the PS2 games. As far as I know all models support software emulation for the PS1 games. Check out http://en.wikipedia.org/wiki/PlayStation_3.
PS1 can but Ps2 you have to download something I think, or get a new system or something. Not positive. Check the faq's at playstation.com
Depends. Certain ones can, while others can't. You have to just try and see.