Combine the beer, peach nectar, peaches and syrup in a large pitcher; stir to blend. Serve immediately.
Place 1/2 cup water, the sugar and ginger in a small saucepan. Bring the syrup to a boil over high heat. Reduce the heat and simmer until the sugar dissolves, about 5 minutes. Let the syrup cool completely, about 20 minutes. Strain before using.