(MONEY Magazine) – A recent survey found that, of the 3.7 million American families now taking care of an elderly relative or friend, more than a third get no assistance from any outside service, agency or home health aide, and nearly one in four has never even picked up a phone to inquire about such relief. Don't needlessly be a part of that large, suffering, go-it-alone group. You can get help ranging from simple housekeeping to full-time nursing assistance, sometimes free or at nominal cost, once you learn to take advantage of the elaborate social service network that exists around almost every sizable U.S. community. Your best local resource is likely to be the nearest area agency on aging (if it's not listed in the Yellow Pages under ''Senior Citizens,'' call the National Association of Area Agencies on Aging at 202-484-7520 for the number). Sometimes the agency will provide service directly; at other times, it will only refer you to nearby organizations that do. But in either case, its members are likely to be familiar with the state and local bureaucracies that serve the aging -- something that will prove especially helpful for kids who take care of their parents from afar. We catalogue below a sampling of other services, sourcebooks and even videos we found valuable.

GENERAL RESOURCES -- American Association of Retired Persons (1909 K St. N.W., Washington, D.C. 20049; 202-872-4700) -- AARP, the 31-million-member service and lobbying monolith, is the mother source. Much of its information is free, such as the pamphlet Miles Away and Still Caring, a guide for helping a parent who lives in another state or city. (The heart of this publication is a master table in which you look up your problem -- such as ''needs help with housekeeping'' -- and read across to find agencies like the American Red Cross and Visiting Nurse Associations that can solve it.) But ask also about AARP's books, such as Homesharing and Other Lifestyle Options ($12.95), for example, which explores alternative housing for the elderly, ranging from group-shared homes to an ECHO house (short for ; elder cottage housing opportunity, essentially a small, self-contained home that you build in your backyard). And don't forget that AARP's Tax-Aide volunteers can help your parents fill out their 1040 forms for free. Membership, which costs only $5 a year, is open to anyone age 50 or older. (For a critique of its many services, see Money's award-winning special report ''The Power and Products of AARP,'' October 1988.) -- Parentcare: A Commonsense Guide to Helping Our Parents Cope with the Problems of Aging, by Lissy Jarvik, M.D., Ph.D., and Gary Small, M.D. (Crown Publishers, $19.95 in hardcover, but a $10.95 Bantam paperback is due out in March) Using real-life cases, the authors address the daunting emotional and practical problems of caring for an aging parent. The book is especially effective in helping you handle the anger and resentment -- and consequent guilt -- that many children feel. The appendix includes a state-by-state listing of medical school geriatric programs that you or your parents can call to find a specialist. -- The Age Care Sourcebook, by Jean Crichton (Simon & Schuster, $10.95) Whatever your worry, this remarkably comprehensive guide has a suggestion for salving it. Suppose, for example, that your widowed father just got home from a heart operation and you fear a relapse. American Medical Alert in Oceanside, N.Y. (516-536-5850) can provide him with a coin-size waterproof radio transmitter that he can wear around his neck to summon help (via an automatic telephone dialing device) even if he can't make it to the phone. It costs $495 and $20 a month thereafter. -- Family Home Caring Guides (NCOA, Dept. 5087, 600 Maryland Ave. S.W., West Wing 100, Washington, D.C. 20061; $6) If you're just starting to care for a parent, this set of eight brochures published by the National Council on the Aging provides concise but solid advice on important issues, from avoiding home accidents to the pros and cons of legal arrangements like guardianship. -- For Those Who Care (Metro-Dade County Elderly Services Division, 305-375-5335) You probably won't want to sit through all nine hours of this video series, much less shell out $100 for the five cassettes. But people faced with the decision of whether to place their parent in a nursing home might consider one of the tapes, The Hardest Decision of All, for $25. -- Parent Care (Gerontology Center, 316 Strong Hall, University of Kansas, Lawrence, Kans. 66045; 913-864-4130) Written for the people giving, not receiving, the care, this lively, six- times-a-year newsletter is essentially a tip sheet composed of book reviews, health advice and hotline numbers. Cost: $20 a year.

HEALTH CARE -- Home Care for the Elderly, by Jay Portnow, M.D., with Martha Houtmann, R.N. (Pocket Books, $8.95) This guide gets down to basics with a step-by-step program for taking care of a disabled or partly disabled person in your home. Especially practical are drawings of simple gadgets that help the infirm help themselves: a long- handled shoehorn for people who can't bend over, for instance, and a button hook for one-handed buttoning. The authors add some interesting commentary on normal aging. Don't fret, for example, if your elderly parent needs an afternoon nap. By the time we reach the age of 60, they say, most of us wake up momentarily (and involuntarily) some 150 times a night, vs. only 10 times or so a night when we're 20. In other words, your mother or father (or you, for that matter) may really need the sleep. -- The 36-Hour Day: A Family Guide to Caring for Persons with Alzheimer's Disease, by Nancy L. Mace and Peter V. Rabins, M.D. (The Johns Hopkins University Press, 701 W. 40th St., Suite 275, Baltimore, Md. 21211; $8.95 plus $2 postage and handling) One person in 12 over the age of 65 suffers from this vicious disease. For help in addition to the book, phone the Alzheimer's Association at 800-621-0379 for the number of your nearest chapter.

HOUSING -- Shared Housing Resource Center (6344 Greene St., Philadelphia, Pa. 19144; 215-848-1220) Here's a national clearinghouse for the many local groups that provide housing for people who can't or don't want to live alone yet don't need full- time care. A referral service only, the center doesn't evaluate the 340 housing agencies and roommate-finding services that it lists. -- American Association of Homes for the Aging (1129 20th St. N.W., Suite 400, Washington, D.C. 20036). Send $4 for the booklet The Continuing Care Retirement Community: A Guidebook for Consumers for help in assessing this concept, in which elderly people put down a lump sum and make monthly payments to live in a group home or a condominium-like development that provides all of their needs. -- The National Center for State Long Term Care Ombudsman Resources (2033 K St. N.W., Suite 304, Washington, D.C. 20006) Behind this forbidding title lies the organization that can put you in touch with a pivotal person: the ombudsman (essentially an advocate for the patient) who monitors nursing and board-and-care homes in your state. You can call the ombudsman's office to check on the history of a nursing home if you are considering checking your parent in -- or, afterward, to complain if your parent is ill-treated by the home. The ombudsman will investigate and can refer your case to the state licensing agency.

INSURANCE -- Medicare Made Easy, by Charles B. Inlander and Charles K. MacKay (Addison- Wesley, $10.95) This comprehensive primer helps you get the most out of the government- sponsored health insurance. Consider an HMO seriously, for example, if your parent anticipates high medical bills. Reason: the many HMOs that have joined Medicare's so-called risk program can't refuse to enroll a person just because he's in poor health. Nor can they terminate his contract just because his bills go sky-high -- that is, unless they terminate all their Medicare contracts, in which case they have to give you 60 days' notice. The last chapter offers troubleshooting advice for problems such as being told that your parent doesn't qualify for Medicare (if he's a citizen, is over 65 or disabled, and has paid Social Security taxes, he qualifies). -- Long-Term Care: A Dollar and Sense Guide, by Susan Polniaszek (United Seniors Health Cooperative, 1334 G St. N.W., No. 500, Washington, D.C. 20005; $6.95) Among the virtues of this thorough work is a tough, 13-point checklist to ponder before buying any nursing-home insurance. For example, make sure the policy includes a ''guaranteed renewability'' clause, which essentially means the company can't cancel the policy, rather than a ''conditional renewability'' clause, which means it can cancel -- or up the price -- at its option.

LAW AND FINANCE -- Finances After 50, by Dorlene V. Shane and the United Seniors Health Cooperative (Harper & Row/Perennial, $10.95) A first-rate guide for the newly widowed spouse who must cope with money matters for the first time, this book doubles as a refresher course for people more experienced with the subject. -- The National Academy of Elder Law Attorneys (1730 E. River Rd., Suite 107, Tucson, Ariz. 85718) A stamped, self-addressed envelope to this group will bring a list of nearby lawyers familiar with seniors' legal problems.

TAKING CARE OF YOU -- Children of Aging Parents (2761 Trenton Rd., Levittown, Pa. 19056) In your concern for your aging parent, don't neglect to take care of yourself. This organization can put you in touch with more than 200 support groups nationwide composed of people with a similar plight. Also, its Care Sharing Directory ($20) lists the names and phone numbers of more than 100 geriatric-care managers, whom you can hire to review your parents' situation and do the legwork for you in locating service agencies and government help. Membership: $15 a year. -- National Association of Private Geriatric Care Managers (1315 Talbott Tower, Dayton, Ohio 45402; 513-222-2621) In case you still can't find a geriatric-care manager using the list above, contact this umbrella group for the profession. For a fee of $50 to $120 an hour, care managers will locate and supervise hirees or volunteers who check on your father, buy his groceries, fill out his Medicare forms and remind him to take his pills.