Watch out if you use fresh tea leaves.
I usually make my own iced tea, but since we have a patch of mint growing out by the barn I thought it would be nice to make some mint tea. The tea was delicious, but it took me forever to get the oils out of the plastic container. I used one step cleaner and dish soap, but every batch of non-mint tea afterwards tasted like mint. Finally a 24 hour soak in oxyclean got rid of the left over oils.
But it does sound like a delicious idea to make a tea/beer. I'm sure herbal teas might add some interesting flavors.