I assume that it could be possible that Sony could release a PS1/PS2 compatibility layer that you have to purchase from the Playstation Store that would allow backwards compatibility.
I have a 60gb PS3 and there some PS2 games that do not work properly even though I thought it was supposed to have the emotion engine chip built in to allow 100% BC.
In the meantime, you can still backup your PS1/PS2 Memory card to the PS3 and then copy the saves to an SD card for safekeeping.
This is interesting, I thought the 40gb PS3's had 0 Backwards compatibility.
That is pretty interesting. I'm guessing they just installed that option on all ps3's to avoid extra work. I think people may be hoping for a lost cause by waiting for a firmware update that allows the use of ps2 games on those consoles.