You can use pretty much any pins for an LCD, check out the LiquidCrystal library
Your buttons can connect to any digital pins set as inputs.
Your FET can connect to any digital pin set as an output. You turn it on with a command like
digitalWrite (13, HIGH); // assuming the FET base it connected to pin 13
You already have the Arduino playground page that describes this.
Where the temperature comes into this I have no idea.
I'm afraid with no further explanation (especially regarding the temperature) there's not much more I can say.
Rob