I don't see why not, I'm pretty sure they're going to be using blu ray disks. Is the PS3 using DL BD or just standard BD?
There's nothing to confirm it, but all the rumors right now seem to indicate the PS4 will not be backwards compatible. I'm too find the links right now but if you look around there are some reasonable arguments for why it probably won't be backwards compatible.
Guess we'll find out on the 20th!