Depending on how it's made the Iced Coffee could be simple coffee with some milk or creamer and some ice cubes added to it.
Or the iced coffee could have the milk, creamer and ice added to it and then blended in a blender to make the iced coffee.
A Frappuccino is usually made from from ice cream, milk and flavored syrup blended together and has a much creamier taste than iced coffee.
The Frappuccino also usually contains no ice unless you want to make an iced Frappuccino which I have done before at home and it's pretty good.