Share your home with a foreign youth. World Exchange, a summer homestay program, is seeking host families for visiting students from France, Spain and Japan for one month this summer. Host families provide room, board, guidance and companionship for the visitors.

The foreign students speak English and bring their own spending money. They visit not as tourists but for the opportunity to become part of an American family, live in an American home and share in daily American activities.

Prospective participants for the program are interviewed and an attempt is made to match families with students' interests and hobbies.

For more information about becoming a host family or enjoying a home stay abroad, call World Exchange Program directors Mike or Melanie Goldammer at 703-690-3588. Keep your New Year's resolution! The American Lung Association of Northern Virginia is conducting a four-session Stop Smoking Clinic for anyone who has a sincere desire to stop smoking.

The clinic will be held at Woodbridge Senior High School, 30013 Old Bridge Road, Woodbridge, from 7 to 9 p.m. on April 8, 10, 14 and 16. The fee is $15.

Stop Smoking clinic participants will learn why they smoke, what triggers a smoking response and how to break a smoking pattern. The program features films, group discussion and instruction in relaxation techniques, and is designed to help smokers quit permanently.

Registration forms may be obtained by contacting the ALANV office at 591-4131. Because space is limited, the registration deadline is April 4. Have some cast-outs or throwaways? The Yorktown High School PTA Library Committee and library staff are seeking the donation of used books (hardbacks, paperbacks and comic books) to be sold at the school's Used Book Sale in April. All donations are tax-deductible.

Books may be dropped off between 7 a.m. and 2:30 p.m., or arrangements can be made for pickup by calling 536-7525, ext. 47.

Yorktown High School is located at 5201 N. 28th St. (off Yorktown Blvd.), Arlington. Proceeds from the April 12 sale will be used to offset the rising costs of school library books. For more information, call Carol Jenkins at 536-7525. The U.S. Coast Guard Auxiliary Flotilla 14-3 is offering a sailing course to begin March 24 from 7:30 to 9:30 p.m. at Lake Braddock Secondary School, 9200 Burke Lake Road, Burke.

The course will include instruction in rigging, points of sailing, helmsmanship, rules of the sea, piloting and heavy weather sailing.

Registration will be at 7 p.m. just before the first class. For further information, call Wilson Wood at 280-2688 or Jim Nelson at 780-0799.