Sprite is good for settling an upset stomach and has worked for years for me when I've had an upset stomach.
The fizz from the sprite helps to replenish the fluids and help with lost glucose when vomiting and having diarrhea.
Ginger ale and other clear sodas are also good to drink when you have an upset stomach and can't keep nothing else down.
You should also drink some water and maybe even some orange juice or apple juice to help provide you with some Vitamins and keep yourself hydrated.