I have used this method of cooking chicken and it works GREAT!
I've never added any flavorings to the beer but it sounds like a good idea. Just buy cheap beer for cooking with, save the good stuff for drinking, the chickens don't care and it makes them super moist. We just cook until the beer is gone and by then the chickens are just right. This works really well when cooking for a crowd!
you have to try to make it dancing beer but chicken. This is also entertaining durring parties. Take the beer and open it only from the tab and get it cooking / cooked down to where it is almost boiling and sloshing in the can thus making the standing chicken "dance" on the grill -Take a little practice but a good time with meat : )