Stray dog adopts our neighborhood

Reports of dog sightings have been filtering in to our house. At sun up we are awakened by howling, I spot a coyote sized dog with a distinctive German Shepard look in our upper driveway. My daughter says she spotted a dog hiding when she came home at midnight. We don't own a dog and our two cats have no doggy friends so when I see the stray outside my office window I bang on the glass hoping to scare it away. I see it turn the corner back into our yard so I walk outside and find it cowering under the car.  On my approach it bolts up the road into a neighbors yard.  That afternoon talking with neighbors, all who have spotted it, I realized the dog had been around for several days, but none of the adults have been able to approach it. The two youngest kids (13 and 9) take it upon themselves to befriend the stray and immediately are successful. Using typical children sounds and doggy treats they  were able to call it over, pet it and soon place a rope around Frisky's neck, (of course they named it) When I approached  Frisky snapped and growled at me while retreating between my sons legs.  Soon enough all of us were able to gather around, but Frisky remained cautious of adults and sought the children for protection.  I have twice driven the local area looking for lost dog signs, I've also checked Craigs List and the lost dog list at the county shelter web site.  Now what?