Peel and dice the peaches. The secret here is to put 4 or 5 of the dices in the freezer so that you add them to your drink later, it will keep it cool and your smoothie wont be all liquefied like if you use regular ice.
put the peach dices in the blender, add the yogurt (choose the flavor you want, natural will make it less sweet) add the amount of milk you judge suitable (you may not add milk at all) and blend.
add the frozen peach cubes and serve.
ps: you may use any other frozen fruit instead, like grapes or raspberries for instance.