Combine the sugar, water, and peach Jell-O in a large saucepan and boil for 3 minutes.

Stir in the peach puree, lime juice, and orange juice. Place in a large Ziploc bag (or a couple of quart-sized Ziploc bags--that'll be easier to use when you're ready to make the slush) and freeze overnight or for several days.

When ready to serve, allow the peach mixture to thaw for 15-20 minutes. Combine the peach mixture with the pineapple sherbet and Sprite in a large punch bowl or drink serving container.

Serve with straws and spoons.