iFixit

Remove the three T8 security Torx screws on the underside of the PS3 slim.

What's that, you say? Security screws? Yes, that's right. These screws have a pin in the center of them that prevents an ordinary Torx screwdriver from working. These screwdrivers are widely available, just not quite as easy to come by as a normal Torx.

Sony did this to prevent people like us from taking it apart.

Those three T8 security Torx screws seem to be the only non-Phillips head fasteners on the entire device.

This seems a little spiteful-- hardware hacking is a fine American tradition. No worries, we'll make sure it's easy for you to get these screwdrivers.