MOSCOW, JUNE 4 -- It opens with President Reagan greeting guests in Russian on one videotape and gives way to rock star Cyndi Lauper belting out songs on another.

It unfolds into a wide-ranging display of even more blatant forms of Americana -- the biggest such show in the Soviet Union in eight years -- including computers by the dozens, a blowup of tennis pro Jimmy Connors, and videotapes alternating pictures of everyone from former senator Gary Hart to comedian Eddie Murphy.

It is "Information America," a multimedia exhibition that opened a nine-month, nine-city tour here today, giving Soviets a heavy dose of the America they can rarely glimpse through the state-controlled media.

With paraphernalia ranging from a computer with printouts in braille to a movie poster for "E.T.," the exhibit makes a gallant attempt to give the feel of America in the 1980s to people unlikely ever to see it.

The $14 million tour grew out of the cultural exchange agreement signed at the 1985 Geneva summit and revives a tradition of U.S.-Soviet exhibition swaps that started in 1959 and lapsed in 1979.

"Our goal," U.S. Information Agency Director Charles Wick told the crowd of Soviets and westerners at the opening, "is to present to the Soviet Union our performers, our artists, our thinkers, our scholars, our politicians, our writers, our dreamers and even that mythical creature -- the average American."

It was the latter, however, that caught the imagination of the spotty opening-day crowd.

One of the most crowded attractions, for instance, was a shopping cart filled with Jell-O, Tang, Cool Whip and other processed foods. It occupied American tour guide Jan Eklund full-time answering visitors' questions.

Soviet poet Tatyana Sherbina called it "the most interesting thing here."

Another crowd-pleaser was a Plymouth mini-van which stood in the middle of one exhibition room with doors open, music blaring and Russians climbing in and out.

But the leitmotif linking hundreds of items on display was the computer -- represented by Apple, IBM and others. Computers for children graced one counter; those for office workers occupied another. One exhibit mapped the march of electronic progress from an old-fashioned telephone to a lightweight IBM PC. Those exhibit booths that lacked computers themselves carried pictures of them at work in places like classrooms and libraries.

"I hope when you see the whole exhibit," President Reagan said in a videotape dubbed in Russian, "you will have a much better idea of how this 'information revolution' has indeed transformed many areas of American life."

With planned stops in such out-of-the-way Soviet cities as Rostov, Tashkent and Tbilisi over the next few months, the exhibit promises to spread Americana in places it has barely seeped before.

"When you get out of the big cities," U.S. Ambassador Jack Matlock said today, "it's the only way for Soviets to make contact with Americans."

An added feature of the exhibit are the guides, 24 Americans fluent in Russian who are already becoming mini-ambassadors.

Asked what he liked most about the exhibit, Soviet journalist Mikhail Segov said:

"I liked the girl running the computer display. She said it was the first official thing she had to do after graduation. And then she blushed."