What should you do if you find an injured bat on your back porch?

I've had a similar situation with an injured skunk. First and foremost, remove pets, and children or anything else that is in danger of being bitten. Next call your local animal control department and explain the situation. If you can close off the porch so it won't get away do that. If he is rabid you don't want him wandering out into the world again. Then wait for the animal control officer. Bats have a very high incident of being rabid and animal control will most likely destroy the bat and test it for rabies. Warning: Do not try to attend to the bat yourself. It does not have to be foaming at the mouth or acting deranged to be infected, my skunk had no signs of illness at all.