Two years ago, it was a jungle gym. This year, the annual gift donated to Arlington's Barcroft Elementary School by the PTA is an Atari 400 computer.

The Barcroft Parent-Teacher Association's effort to equip the public school with a computer is part of sudden efforts to push Washington area schools into the computer age. Parents, students and community groups -- alerted by the popularity of video games and personal and business computers -- are increasingly convinced that computer terminals soon will become as common as the telephone and as useful an educational tool as the typewriter.

And now, they say, is the time to start educating youngsters about them. "Computer literacy," it is dubbed.

"Suddenly it's a hot issue," says Marvin Koontz, director of instructional technology for Fairfax County Schools. Jerry Berry, the county's coordinator for computer programs, explains why: "People are aware that students don't have to be engineers or systems analysts to use computers. They know if students have certain computer skills they have advantages over other people who don't."

The result has been that in just the past two years parent and citizen groups in Arlington, Fairfax, Montgomery, Prince George's counties and the District have pressured school officials through detailed reports and public meetings to put more computers in schools and make them available to even the youngest students.

Student enthusiasm parallels that of their parents. Since 1980, career-oriented courses offered at Prince George's County's Bowie and Eleanor Roosevelt high schools have jumped from two to about 24 due to student demand, said assistant superintendent Daniel Chase. "The demand is far greater than what we can do," he says.

Indeed, training teachers, equipping schools with enough computers to give all students regular practice time -- as many parents want -- and purchasing software is an expensive proposition. Budget-conscious school officials are approaching computer training differently -- some aggressively, others with caution.

Once a week, Erol Labosky, Deborah Skelley and Cindy Harmon -- 11-year-olds in Mrs. Janie Baer's sixth grade class at Patrick Henry Elementary School in Alexandria -- each sit at a TRS-80 Radio Shack microcomputer, punch out names and numbers on black keyboards and watch them flash across a silver screen.

This year, all of Alexandria's kindergarten-through-eighth grade pupils are learning about the everyday role of computers and how to use them in courses once available only in high schools. About $400,000 has been spent to equip classrooms and libraries throughout the Alexandria system.

Montgomery, Fairfax and Prince George's counties and District schools also run programs that officials say will be expanded next school year. The District is this school year spending $1.1 million; Fairfax $700,000; Montgomery $300,000; Prince George's $250,000. Arlington's expenditures for computer training trails behind at $47,000. In Montgomery and Fairfax counties, all eighth and ninth graders are expected to have completed computer literacy courses by next year.

"Take a look at the classified ads," says Alexandria Schools Superintendent Robert W. Peebles. "To ignore what's happening in technology is to go backwards."

In Arlington, a public task force is trying to persuade school officials to approve similar computer programs for the next school year. Despite paring down its budget requests from $400,000 to $240,000, the group has had no assurances from officials who say they are moving cautiously.

"We definitely must address it," says Arlington Schools Superintendent Charles Nunley, "but we're not going to throw a quarter of a million dollars at it." In Arlington and other school systems, computers have typically been used in high school science, math and business courses.

But many parents believe computers should be used in other courses too. Before the current school year is out, the Barcroft PTA in Arlington will have furnished that school with three computers, organized a series of six-week, after-school sessions and paid for a computer training course for teachers and staff.

"We're doing it because the county has not yet gotten itself together," says PTA president John Tuccillo. "This is one train our kids can't afford to miss."

A recent study by the federal Office of Technology Assessment found that educational systems nationwide are dragging their feet into the computer age, primarily because of the high costs. OTA proposes using federal funds to defray costs. Meanwhile, congressional committees have approved a bill giving tax credits to firms that donate computer equipment to schools. Moreover, a Scholastic Aptitude Achievement Test in computer science will be offered to high school students nationwide within the next two years.

Despite the recent push, computers are not new to schools. By the early 1970's most used computer terminals linked to a central computer for administrative tasks and teaching data processing. But the development of microcomputers, self-contained units priced as low as $400, has brought on a revolution.

Arlington students recently programmed a computer to project inflation's impact on the price of a cup of coffee through the year 2200. "You could go in a 7-Eleven with a trillion dollars and come out with no change," teacher Michael Johnson says. And educators are expecting a day when computers are used to drill students in everything from spelling to French, though school officials say widespread use is at least five years away.

They also counsel caution: "I think we're going to have to look at children and the individual ways they can learn," says Alexandria assistant superintent Donald Dearborn, coordinator of that system's computer program.

But some argue that advanced uses are nearly here and that students used to playing computer games at the corner arcade or at home are bored by introductory courses. "We're finding more and more kids are coming into the schools with strong backgrounds," says Berry. "We're going to need more advanced classes."