I don't see why a ps1 Gameshark can't be used on a ps3. It's disc-based after all. You might have to type the code in every time you boot the game, but I can't think of a technical reason why it wouldn't work. It's also easy enough to find on Amazon.
Signed. But just so y'all know, they're a bit shady with donations. I think it's a good petition site, but I wouldn't give them any money, as it likely doesn't actually help the cause.