Holly Phillips, 24, wrote a $333 check last week for a 10-day foreign exchange trip next month, and she had no idea what country she would be visiting.

Late Sunday afternoon, before Phillips could say, "Ich kann nicht Deutsch sprache, (I cannot speak German)," she was oohing and aahing with 250 other Northern Virginians when they discovered they were to travel to West Berlin Nov. 6.

Their counterparts, the West Berliners, are expected to arrive Nov. 7 at Dulles International Airport to be met by Northern Virginian hosts. There will be no hotel or food bills to pay. Travelers from both countries will stay in private homes and eat home cooking.

Known as the Friendship Force, the nongovernmental program was chartered in March 1977, in Georgia to promote friendship and understanding among U.S. citizens and citizens of foreign countries. Already, 14 exchange flights have been completed between 11 U.S. states and countries including Ireland, Venezuela, Israel and Belgium.

President Carter put forth the idea in 1973 when he was governor of Georgia. Rosalyn Carter, who is now the organization's honorary chairwoman, and 200 other Georgians exchanged homes with Brazilians last year.

The purpose is not to provide a "cheap vacation, a business trip or to visit a sister. It's to be a good sport, a good American," Inger Rice, Virginia Friendship Force director, told the Northern Virginia travelers who were briefed Sunday at Langley High School in McLean.

Indeed, the organization's leaders have tried to discourage casual tourists by disclosing the secret exchange city only after all the participants have been selected and have paid their $333. In addition, luggage is limited to 44 pounds and visitors cannot return with more than $50 worth of purchases and gifts.

The bulk of the $333 fee pays for transportation. Each traveler's host supplies room and board. Because the program aims to send a cross-section of residents, $25 from each fare will be set aside for financial assistance to residents who may not be able to afford the trip.

A computer selects and matches the visitors and hosts according to occupation. During their trips, the visitors will spend one day travelling each way, four days in the home of a host and another four days traveling independently or living with another host family, according to program plans.

"I almost jumped right out of my skin" when she was accepted, said jeanne jordan, a Vienna resident. Because her application was approved on short notice, Jordan said she will have to take leave without pay from her job.

"I'd like to go to help the image of the Americans," she said. "You know, we're regarded as the Ugly American. Well, I want to show them that we are normal human beings."

She then ran off to several tables set up in the school lobby to gather information packets, passport applications and sign up for language workshops. Later, all the travelers gathered in the auditorium to receive quick lessons in international relations.

"Don't expect to learn German in three weeks," said Eric Wilmeth, the upcoming flight's troubleshooter. The purpose of the workshops is to teach the basics of survival, he said.

Niels Hansen, deputy ambassador of the Federal Republic of Germany, briefly told the audience about his divided city's history, politics and culture.

"You are ambassadors now, a higher rank than myself," he joked. Hansen then urged the American travelers to cross the Berlin Wall. "Pierce the other side, and compare East Berlin to West Berlin," he said. With that, he invited the crowd to a party Nov. 1 at the West Germany embassy on Reservoir Road.

While most "ambassadors" from previous trips have praised the Friendship Force, some have complained that propaganda and tokenism characterize the program. A shortage of hosts and the inability to correspond ahead of time with guests have caused unpleasant trips for others, they said.

Because of unexpected illnesses, two persons already have canceled their flights, Wilmeth said. Friendship Force will accept applications for replacements for the two persons who have canceled as well as for hosts from Northern Virginia until the day before the trip, he said. Interested persons should call the Friendship Force at 827-7084 between 10 a.m. and 4 p.m., Monday through Friday.