http://hitchhikingtoheaven.com/2012/05/homemade-orange-soda-syrups.html
It basically says to blanch some orange zest and set it aside. Then put 2 cups water, 2 cups sugar and 1/2 tsp Citric acid (i happened to have some on hand since I made bath bombs for christmas last year) in a pan and simmer for 15 - 25 mins until it gets thicker. Then you add about 1 cup of orange juice (preferably juiced straight from the orange) and it's ready to use as a Soda Syrup. Well I didn't have a juicer but i figured my Blendtec could do the job :) So I just threw some oranges in the blender and then strained out the pulp. It worked pretty well except next time I think I will get some cheese cloth or a finer mesh strainer because there was still some fine pulp in my syrup.