people seriously need to learn what the search bar is for.
I take it I'm going to be answering this question forever too:
backward compatibility for the PS3 with PS2 games is as follows:
20GB (4 USB slots, no longer in production) - yes
60GB (4 USB slots, no longer in production) - yes
80GB with 4 USB slots (no longer in production, bundled with MGS4 or Motor Storm) - yes
40GB (2 USB slots, no longer in production) - NO
80GB with 2 USB slots - NO
160GB (2 USB slots) - NO
any other up coming PS3's - NO
in short: if it has 4 USB slots, yes. if it has 2 USB slots, no.
all PS3s play PS1 games.
http://en.wikipedia.org/wiki/PlayStation_3#Models
the download that others may refer to is for backwards compatible PS3s ONLY!!!!!!!!!!! a download will NOT make a non-backwards compatible PS3 play PS2 games. PERIOD!
"If a PLAYSTATION 3 is not backward compatible, you will not be able to add this function through any hardware (i.e., changing the hard disk drive) or software (i.e., updates, homebrew) upgrades or modifications. "
that came DIRECTLY from Sony's own website: http://playstation.custhelp.com/cgi-bin/playstation.cfg/php/enduser/std_adp.php?p_faqid=232&p_sid=1P9bCDwj
there is a RUMOR going around that Sony may be able to make a patch that will allow all non-backwards compatible PS3s play PS2 games. it is just a RUMOR right now, but it may happen. they say that no software update would make PS2 games play in a PS3. but they also said it wasn't possible to have Dual Shock in the Six Axis controller. and that controller has been available for a while now...
if you do own/buy a PS3 that is backwards compatible, not all games may work. to see if there are any compatibility issues with your console and a PS2 (or PS1) game, check this site: http://www.us.playstation.com/Support/CompatibleStatus