Combine sugar and water in medium sized saucepan. Stir over medium heat until the sugar dissolves, then bring it to boil. Transfer to 11x7x2-inch or similarly sized glass dish and chill until cold, about 2 hours.
Puree cantaloupe in blender until contents are smooth. Add to sugar and syrup dish and stir until well until everything is blended. Freeze until it is nearly firm, stirring occasionally, at least 2.5 hours.
Transfer cantaloupe mixture to large bowl. Using electric mixer, beat until fluffy. Return to freezer and freeze until firm (no more stirring!), at least 2.5 hours.