Arduino +Sparkfuns 4-digit 7-segment 16pin display

I was just wondering how to program the Arduino to make the 4 digit 7-segment display show a number that was arrived at in a different part of the program. I would be using the red display, so would it be different than Hari's post? I think I may have to use an Arduino Mega since I'm already taking up 8 digital pins with other things.