In a medium saucepan, stir together water, sugar, peaches and raspberries. Bring mixture to a boil, then reduce heat and let mixture simmer until sugar is completely dissolved. Remove from heat, cover and let steep for 25 minutes.
While the syrup is steeping, make tea. In a large pot bring water to a boil and steep tea bags in water 3-4 minutes or until tea is to your desired strength. Once brewed, remove tea bags and transfer to a pitcher then refrigerate to cool.
Once the syrup mixture has steeped, pour over a fine mesh strainer to removed fruit pieces (fruit can be reserved for another use). Chill in the refrigerator until ready to use.
After both the tea and syrup have chilled, pour syrup into the tea*, stirring to combine. Serve over ice and garnish with additional peach slices and raspberries if desired.
Notes
*Alternatively syrup can be kept separate and stirred into individual glasses of tea