Prevent a Litter Coalition (PaLC) - Dedicated to ending the tragedy of surplus, homeless and abandoned pets resulting in the euthanasia of millions of adoptable animals each year, by defining the community wide issues, increasing public awareness of the problem, promoting humane and responsible pet care... and by providing a forum for effective collaboration between those who share our mission.

SpayUSA - SpayUSA, a program of The Pet Savers Foundation, is a nationwide network and referral service for affordable spay/neuter services.

Stop Abuse -- Don't Litter - Each year thousands and thousands of cats and kittens, dogs and puppies are euthanized due to overpopulation. Statistics show that 10-12 million pets are euthanized annually in the United States. Using the lower figure of 10 million, that's 192,308 per week or 27,473 pets euthanized every 24 hours, 365 days a year.

The Myths and Facts of Spaying and Neutering (Petsmart) - The animal population is exploding. Each year millions of unwanted pets are born and most are treated like "living garbage" and disposed of. The primary causes of pet euthanasia are the failure by owners to have their pets spayed or neutered and animals that are abandoned or relinquished to shelters because of obedience problems. This is tragic and reprehensible ... but also preventable.

Responsible Pet Ownership: Pet Overpopulation (animed.org) - It's not a virus and it's not a bacterium, but it is responsible for the deaths of millions of animals annually. This disease does not discriminate. It strikes dogs and cats, kittens and puppies, purebreeds and mix-breds.... it is pet overpopulation, and it is the biggest problem facing animal shelters today.

Why You Should Spay or Neuter Your Pet (HSUS) - There are many compelling reasons to spay or neuter your pet. Find out why spaying and neutering are good for you, your pet, and your community.

Love That Cat - this site lists programs that provide low cost or free spay/neuter for cats. Some programs work only with pets of people with low incomes. Some do not consider income but serve only pet cats -- or only feral (untame) cats. But other programs serve all kinds of people and cats.

Spay or Neuter surgery (Dog Owner's Guide) - Spay and neuter surgery to sterilize dogs and cats has been hailed as an expedient method of pet population control. The idea, obviously, is that sterilized pets can’t breed and produce puppies that end up in animal shelters to be adopted or euthanized. Many shelters and virtually all rescue groups sterilize dogs before making them available to buyers, and many shelters that do not do the surgery before the animals leave do require that the new owner do so.

House Rabbit Society Spaying and Neutering FAQ - When being conscientious about the pet overpopulation, don’t forget to spay or neuter your pet rabbit. Altering rabbits can reduce hormone-driven behavior such as lunging, mounting, spraying, and boxing. Spaying females can prevent ovarian, mammarian, and uterine cancers, which can be prevalent in mature does. Also, rabbits reproduce faster than dogs or cats and are the third-most surrendered animal to shelters. (This bit of information about spaying rabbits taken from the Humane Society.