A few really dedicated people can do so much. The Volunteer Association for the Protection and Care of Animals in Tijuana, Mexico, an organization that cares for street dogs and cats, was written up a few months back. "Tijuana clinic rescues animals, sets adoptions" tells how a grassroots group with just 22 active members runs sterilzation clinics, adoption events and teaches responsible pet ownership to schoolchildren. They have no shelter; members keep rescued animals in their homes until they are adopted. Their website has before and after pictures of rescued dogs, but since I just post "happy animal" pictures on this site, here's one of a recently adopted, happy puppy from their site.

Photo: from ASOCIACIÓN VOLUNTARIA PARA PROTECCIÓN Y CUIDADO DE ANIMALES website