Sony has put back rewards compatibility for PlayStation 1 (PS one) games in the new PS3 Slim. It has not been since the 60GB PS3 that there was the ability to play PlayStation 2 games on a PS3. Unfortunately it is not possible to buy a 60GB version anywhere as it was discontinued several years ago. Many people want the PS3 to play Playstation two games, and you know what, that's possible and will probably happen in the future on the system, let me explain.
The system already has the ability to play PlayStation two games if it wanted. Sony can easily allow users to play PS2 software in a software update on the PS3 Slim. Simple is not it. The ability to play PS2 games on the PS3 was removed to keep the PlayStation 2 selling.
The reasons Sony took the ability to play PS2 games away in the first place was because the last generation console was still selling a little. Sony felt there would be no reason to keep a PS2 on the market with the PS3 having returns compatibility for Playstation 2games, therefore Sony removed the ability to emulate PS2 games from the PS3 to boost PlayStation 2 sales.
I really think that Sony will add the ability to play second generation software on the new console in the future, just once the old console stops selling, that is. I think this is something that we will be seeing in the future, once the PlayStation 2 has become defunct expect those older games to be playable on the system near you soon!