Instructions
Determine what PS3 model you have. The only 80GB model that contains backward-compatibility is the model that originally was released in August 2007.
Locate the serial number. Find the white tag on the lower-left of the back of the console that reads "SERIAL" and is followed by a string of numbers and letters.
Read the final seven characters in the serial code. If they read "CECHE01," then your 80GB PS3 is backward-compatible. If they read "CECHK01" or "CECHL01," your system won't work with PS2 games.
Determine whether the PS2 game you wish to play is backward-compatible. Various websites list which games are compatible.
Insert the PS2 title you wish to play into your PS3 and power on the console.