A PS2 is like 30 bucks max, so it's not hard to go pick one up if you need one.
Oh i think that you're very lucky to have the backwards compatibility in your Playstation 3 and i think that if you wanna sell it you will earn a lot of money from it just because of that special feature.I am one of the few lucky ones that decided to buy a PS3 on the month when it first came out. 60GB "fat" models have backwards compatibility which means you can play any PS1 or PS2 game on your PS3 as well. It is something I take for granted but I would never give my PS3 away because the backwards compatibility is my favorite feature. I can easily switch out my favorite PS3 game with my favorite PS2 game .