Here is a quick tutorial on how to make elderberry syrup.
http://honest-food.net/2011/08/04/how-to-make-elderberry-syrup/
Check out other great tutorials and recipes from Hank Shaw if your get inspired or order his book: Hunt, Gather, Cook: Finding the Forgotten Feast for wonderful ideas on eating wild foods and preparing incredible dishes.
Also check out and join the conversation about harvesting and using elderberries here at PP: https://www.peakprosperitycom.bigscoots-staging.com/discussion/82322/elderberries