put up a poster in your local shop with your number or a number available and on the poster say that your responsible. you should also put your age. dont put out too much information. also make leaflets and drop them into peoples door.
talk to your nieghbors and let them know. tell your friends to tell their parents if they have younger children.
Put an ad on the craiglist.com and add it on the job listings for people to view your informations.
Just easily let them now that you are 100 percent available :)
get a microphone and announce it to the world! (: