It's Saturday morning and the old gangs are uploading and downloading all around town.

Like Harry Mileham, 79, a retired USDA worker, leaning against his borrowed computer in a George Mason High School classroom in Falls Church, observing that "lots of older folks are over-awed or scared by these things, but they're really no more frightening than a microwave oven." He belongs to a local senior group, The Computer Generation, which offers access to a national telecommunications network called SeniorNet.

Or take Tanya Metaksa, 50, a computer specialist, explaining the mysteries of word processing, spread sheet and data base management in Maryland's Holton Arms School computer lab to graying men and women who joke they should be known as "elder bytes." Over the past three years, the nonprofit program, "Computer Learning for Seniors," has nurtured a "couple of hundred" area dilettantes through its training classes.

Experts say that older students have special qualities that help make computer learning easier: patience and persistence. And often they have more time.

Maybe not surprisingly, the idea of merging computer literacy into an aging society began here in the nation's capital.

In 1983, Greg Kearsley, 32, and Mary Furlong, 34, educators at Catholic University, acting on a hunch that seniors might not want to be considered too old to learn new tricks, packed a car with $10 used TV sets and $75 computers from Toys-R-Us and set out for church basements, computer clubs, nursing homes and retirement facilities in the District, Silver Spring and Alexandria. Their aim was to size up the interests, abilities and needs of the over-60 crowd in computer technology.

"Nobody had any idea who we were, but the response was terrific," says Furlong.

The young professors ended up juggling hands-on workshops for 300 Washington area adults ranging in age from 60 to 95 years. Their simple courses were created to show that computers can be fun, useful, challenging and -- especially for the elderly -- a link to the outside world. From this effort came the input for a large-print paperback book, Computers for Kids Over 60 by Kearsley and Furlong, followed by their blueprint for a national experiment called SeniorNet.

Now in its second year, based at the University of San Francisco and funded by the John and Mary R. Markle Foundation with equipment and software support supplied by the Apple Computer Co., SeniorNet has about 400 seniors at 10 research sites across the country, including Falls Church. The SeniorNet basic training course offers elders a cursory introduction to computer usage, information retrieval and telecommunications, and a few hours on-line on the network learning how to exchange interpersonal chit-chat or researching, say, the latest information about Parkinsons' disease or tax benefits or participating in monthly national conferences led by experts on issues such as health and social security. Those in the research plan pay no fee. An additional 800 or more older buffs with home computers and an interest in networking are charged $5 membership dues and $8 per hour for nighttime use of SeniorNet.

"Some of us use SeniorNet like a ham radio or a CB. I can't travel as much as I once did, but I can spend my evenings roaming the United States with great joy," says Joan Elswit, 63, Oakton, a retired graphics artist who has become so proficient with computers that she now teaches other retirees in the Falls Church program.

Nancy Birindelli, coordinator of Community Education, Falls Church Public Schools, whose division has been part of an ambitious program to serve the estimated 30 percent senior citizen population of Falls Church, says the introduction of seniors to computers has been "one beautiful experience." When the SeniorNet experiment was announced last year, so many signed up that five extra classes were added.

This summer, user-friendly repeaters came back clamoring for more advanced learning, and the entire high school computer lab facilities were opened for afternoon and Saturday instruction. The old-hands gave their expanded program a new name: "The Computer Generation." While many continue to access SeniorNet and practice on donated Apple computers, others now are concentrating on mastering IBM compatibles, learning more advanced word processing techniques for writing letters or books, devising simple data bases to keep track of telephone lists, insurance and bank records, using the modem for the big bulletin boards where they can shop and reserve airline or theater tickets. A new added attraction: up to 70 minutes per day free on the local bulletin board, "Insight," which is operated by the Reformation Lutheran Church on Capitol Hill and has a special sector for seniors.

The Falls Church project currently costs $50 for 12 hours of instruction -- city residents over 65 can apply for a tuition waiver. According to Robin Hopes, a special education teacher who coordinates the program, a hard-core group of eager students -- who may or may not own personal computers -- pay an extra $5 on Saturdays for three more hours of instruction -- and camaraderie.

Out in Montgomery County, "Computer Learning for Seniors" is a relaxed group organized to help over-50 amateurs delete apprehension about such technical babble as MS DOS. A registration fee of $25 pays for five introductory classes on IBM-compatible machines.

Tanya Metaksa says "all sorts" of people show up -- retired military personnel, government workers, policemen, housewives, especially "those who wouldn't jump into classes with the more intense, high-powered, PC types."

The new president of Computer Learning for Seniors, Selig Starr, 68, a retired federal government employe, thinks that aging students "seek exposure" to computers for very practical reasons. Skeptics look for an inexpensive way to decide whether they really need to purchase a computer in order to keep abreast of the times. Experienced workers with the sinking feeling that their skills are increasingly obsolete want to test their potential capabilities. Dejected and overwhelmed owners of new computers with bewildering manuals about hardware and software quest for hands-on practice in a laid-back setting under the tutelage of empathetic experts. Grandparents join classes because they want to stay in touch with their families.

In the less pragmatic view of the Rev. Brian Hughes, a pastor at Reformation Lutheran Church who coordinates the Insight bulletin board, these programs, "tend to attract people who like people."

Opportunities for more senior projects in the local area may be limited only by the scarcity of facilities and the dearth of volunteer trainers. Clearly, owning a computer is not a prerequisite -- in a recent class of a dozen newcomers in Falls Church, no one had bought a computer yet. Nor is the fear of failure or making a fool out of oneself deemed a valid excuse to ignore computer learning. Most older students admit to some initial confusion and frustration -- but point out that when you're with your peers, it's not humiliating to be taught how to look at a screen through bifocals without wrecking your neck. Moreover, there is the unexpected bonus of comfortable intimacy from communicating across the miles with new friends who recognize references to things like the "Dust Bowl" or sugar stamps. The satisfaction of acquiring the technical expertise to format a disk or use a modem, the thrill and intellectual stimulation of embracing a new concept that assures a lifelong education, the satisfaction of opening up creative avenues of personal expression -- all are cited by those determined to enjoy their later years.

And then there's senior clout. Furlong fantasizes about the potential power of a society of computer literate older men and women. She says: "Imagine thousands of senior citizens on-line discussing a piece of legislation, then agreeing to take a position and flooding Congress with personalized electronic mail. Or holding an international conference to personally reflect about war and lay out plans with their grandchildren to mobilize for peace. How about that for making a difference throughout the course of Life?" Mary Finch Hoyt is a Washington free-lance writer.

Among resources for more information:

The Computer Generation. Robin Hopes, Community Education Office, Falls Church Public Schools, 7124 Leesburg Pike, 22043; (703) 241-7676.

Computer Learning for Seniors. Selig Starr, 2210 Mark Court, Silver Spring, 20910; (301) 588-7457.

Insight bulletin board, Rev. Brian Hughes, Reformation Lutheran Church, 222 East Capitol St. NE, Washington, D.C. 20003; (202) 543-2146.

SeniorNet Project. Mary Furlong, University of San Francisco, School of Education, San Francisco, Calif. 94117; (415) 666-6505.

Computers for Kids Over 60, by Greg Kearsley and Mary Furlong (Addison Wesley Publishing Co., $9.95).

For a list of institutions offering introductory computer courses: Elderhostel, 80 Boylston St., Suite 400, Boston, Mass. 02116.