The fastest way to go from zero to a tall and delicious glass of iced coffee is to brew hot coffee and pour it over lots of ice (see, I told you it was easy). If you choose this method you are going to want to make your coffee extra strong because the rapidly melting ice will dilute it. Or you can do what I like to do and use Coffee Ice Cubes.
Of course, you could also let your coffee sit in the fridge for a few hours to cool off, but this defeats the whole purpose. Remember, we want it fast…as in now!