Summarize the following:
The organization may have a contact person or "volunteer coordinator" who can help you get involved at their facility. Visit a shelter's website, and check for any information that is listed for volunteers.  Some shelters will not offer much information on their websites, and some may not have websites at all. Look online for shelters near your home or office. Consider the distance from your home, the type of animal, and the needs of a given shelter. If two animal shelters are right next to each other, but one of them is in more urgent need of volunteers: it may be best to choose that shelter. Most shelters take in dogs and cats, but you may be hard-pressed to find a center that deals with more exotic pets. You may be able to choose between working with dogs and cats, or you may be asked to deal with both. Bear in mind that you may not even be allowed to work with the animals at first. You often need to work at the shelter for a while before you can handle animals directly. Depending on the shelter, you may be assigned to a specific job, or you may perform various tasks as need arises. You may be required to complete a certain number of hours of support tasks before you are allowed to work directly with animals. Laundry, dish-washing, floor-mopping, and office work are often necessary to keep a shelter running smoothly.  Ask about volunteer programs on- and off-site. Most shelters need people to help in the facility: walking dogs, handling cats, and grooming various animals. However, many shelters also have off-site adoption events or fundraisers with which you might be able to help. If you have any special skills that relate to shelter work: tell the shelter! Volunteers can provide website support, offer legal aid, donate medical services, photograph adoptable animals for the adoption websites, or even create and donate original art for sale to benefit the shelter. Most volunteer opportunities occur during a shelter's open hours, although you might also be asked to care for animals and do maintenance work during the off-hours. Shelters are usually open seven days a week, with slightly fewer hours on Saturdays and Sundays.

Summary:
Contact your local animal shelter or humane society. Consider which animals you want to work with. Learn about the available volunteer positions. Make sure that volunteering will fit with your schedule.