In a small heavy saucepan, combine the sugar and water and cook over low heat, uncovered, for 5 minutes or until the sugar dissolves.
Cool the syrup for 30 minutes, then refrigerate, covered, for 4 hours.
In an electric blender or food processor, whirl the peaches for 1 minute.
Add the syrup and lemon juice and whirl for 30 seconds or until blended.
Freeze in an ice cream freezer following manufacturer's directions, then proceed to Step 5, or freeze in a 13"x 9"x 2" pan until firm about 3 hours.
Remove the pan from the freezer.
Break the ice into chunks and transfer to the large bowl of an electric mixer.
Beat at high speed until light and fluffy.
Spoon into a 1/2 gallon freezer container, cover, and freeze at least 4 hours before serving.