Blanch peaches by immersing into boiling water for 30 seconds. Immediately remove peaches and place in a bowl of ice water to cool. As soon as they are cool enough to handle, peel the peaches.
Slice peeled peaches into a blender or food processor. Add sugar and ice. Blend until smooth. If necessary, add a little water to help it blend. You may also add more sugar if the peaches are especially tart.
Divide the peach mixture among four wine glasses. Pour 2 ounces of ginger ale into each glass, then fill to the top with champagne.