In a medium saucepan, combine water and sugar. Cook over medium heat until sugar dissolves, stirring occasionally. Remove from heat and cool.
Add the orange and lemon peel and juices to the sugar mixture. Cover and let stand at room temperature for 1 hour.
Strain the juice mixture. Cover and refrigerate until serving time.
To serve, fill glasses with equal parts fruit mixture and water. Add ice and serve. If you like, garnish the lemonade with citrus slices. Makes 12 (8-ounce) servings.