So you want to join a research expedition ...

Wanted: 15 field researchers. No experience necessary. Must be curious about the world and willing to follow monkeys around the forest in Madagascar. While this may sound like a talent search for an episode of ''Wild Kingdom,'' it's actually business as usual for Earthwatch.

This nonprofit organization, headquartered in a brick mansion here, serves as a link between the public and the scientific community. Researchers apply to Earthwatch for funds and a certain number of volunteers to help with their projects.

Since its founding in 1971, Earthwatch has put more than 6,000 volunteers on field expeditions in 30 states and 55 countries. Most of these people come from nonscientific backgrounds.

''It's a workaholic's vacation,'' says an Earthwatch spokeswoman.

Expeditions have found their way into some of the most remote corners of the Earth. Last year, a group studied underground housing in northwest China, while another worked on excavating a crusader castle in Cyprus. The all-time most popular expedition, however, is an archaeological dig on the Mediterranean island of Majorca.

For those hankering for the less exotic, there are expeditions closer to home - such as studying black-tailed prairie dogs in South Dakota or salt marsh ecology in Massachusetts.

Volunteers pay to take part in expeditions, thereby underwriting the cost of the research. The two-week trek to Madagascar, for instance, costs $1,950, not including the roundtrip airfare to Paris - where volunteers will assemble in November. In general, expedition prices vary from about $500 to $2,000. And since the fee is considered a donation to scientific research, both the fee and the airfare are tax deductible.

''We provide a way for citizens to contribute directly to the work of researchers while also giving the two groups access to one another,'' says Brian Rosborough, the president of Earthwatch. Volunteers learn about the scientific discipline, such as archaeology or zoology, while carrying out basic field research.

Earthwatch has become one of the largest sources of private funds for field research in the US, distributing $1.2 million in 1983 to support 82 different expeditions. Both National Geographic and the World Wildlife Fund will give out about $2.5 million this year.

These figures, however, still pale when compared with the bankrolls coming out of Washington. For example, the National Science Foundation, a federal agency, will spend more than $83 million this year just on Antarctic research.

The creation of Earthwatch ''was really a call by scientists to support privately what we've always supported publicly through the federal government,'' Mr. Rosborough says. At the same time, the use of paying volunteers makes possible projects that would have been infeasible using professional researchers or students.

One labor-intensive project, for instance, involves mapping coral reefs near the island of Bonaire in the Dutch West Indies. Earthwatch divers have logged more than 5,000 dives since 1979, sketching and photographing reef formations and cavities.

''They've mapped tens of thousands of organisms,'' says expedition leader David Kobluk, a petroleum geologist from the University of Toronto. The work will eventually yield the largest, most detailed map ever attempted of a coral reef.

About 10 percent of the volunteers receive some sort of scholarship, provided by corporations and foundations. One California foundation, for instance, gave funds last year to help 50 high school students take part in expeditions.

The researchers, meanwhile, do what they can to dispel any romantic notions volunteers might have about the work. Much of it, says primatologist Alison Jolly of Rockefeller University, is ''quite routine and boring.''

Dr. Jolly, who will lead her first Earthwatch group to study ring-tailed lemurs and sifakas monkeys in Madagascar, says she has no qualms about taking novices into the field.

''After all, you don't need a PhD to look at your watch and say 'I've been here 10 minutes and they're still asleep,' '' she says. Volunteers will track the monkeys' movements, noting time and position on a map. The data will be used to study population patterns and group behavior.

While Madagascar monkeys make for a popular project, some expeditions are harder to sell. This is where Earthwatch marketing savvy comes in. Each expedition has a maximum and minimum number of volunteers, although the price stays the same regardless of how many finally sign up.