In a saucepan, combine water and sugar over medium heat. Bring to a boil, reduce heat and simmer for 5 minutes, stirring occasionally, until sugar has dissolved. Take the pan off the heat and allow the syrup to cool.
In a 6 to 8 cup capacity pitcher, combine the cooled water/sugar mixture, POM juice, cranberry juice and sparkling water.
To each glass, add a slice of lime and a sprig of mint. Pour the bellini mixture into the prepared glasses and serve.