There are many ways to help the animals.  Here are some suggestions:   

SPAY/NEUTER.  Spay and Neuter is one of the most important keys to reducing pet over-population.  Spay and neuter your pets, and help educate the community on importance of spay and neuter.  

VOLUNTEER.  Animal shelters and rescue organizations are always in need of volunteers.  Even if you only have a few hours a week, these few hours spent with animals will be one of the most rewarding moments in life.  

FOSTER.  Fostering saves lives by taking in an animal temporarily until a home is found.  Los Angeles Animal Services have foster programs for animals of all ages; from unweaned puppies and kittens to senior animals.  Also, many rescues cannot save more animals unless they have fosters.

ADOPT.  Adopting a shelter animal saves two lives.  You will be saving the life of your new companion by vacating a kennel or cage space, so that another animal at the shelter will have more time to find a home of his/her own.

DONATE.  Contact your local animal shelter to find out what items are needed.  Most rescue organizations are non-profit and volunteer based, and rely solely on donations to operate.  

Here are some of my favorite organizations:  

A Dog's Life Rescue: http://adogsliferescue.org

Angel City Pit Bulls: http://www.angelcitypits.org

Angel Dog Foundation/Deaf Dog Ranch: http://angeldogsfoundationdeafdogranch.org

Angels in Fur Dog Rescue:  http://angelsinfurdogrescue.com

A Purposeful Rescue:http://www.apurposefulrescue.org/

Bullies and Buddies: http://www.bulliesandbuddies.com

Carrie Ann Inaba Animal Project: http://www.caiap.org

Cat Connection LA:  http://catconnectionla.org

Concerned People for Animalshttp://www.concernedpeopleforanimals.org

Downtown Dog Rescue: http://www.downtowndogrescue.org

Fix Nation: http://fixnation.org

Ghetto Rescue Foundation: http://www.ghettorescueffoundation.org

Los Angeles Animal Services: http://www.laanimalservices.com

Lifeline4Paws: http://www.lifeline4paws.org

Meade Canine Rescue: http://www.meadecaninerescue.org

MuchLove Animal Rescue: http://www.muchlove.org

Muttville Senior Dog Rescue: http://www.muttville.org

Spay4LA: http://www.spay4la.org

Tails of the City: http://tailsofthecityrescue.com

Take Me Home: http://www.takemehome.tv/index.html

The Pepper Foundation: http://thepepperfoundation.org