This week the 1,000th legal au pair of the AIFS (American Institute for Foreign Study) program entered the United States. During the two-year experimental time period, more than 3,000 legal au pairs will be placed through the following two programs:

Au Pair in America, sponsored by AIFS, handles placements nationwide. For more information write: Lauren Kratovil, director, Au Pair in America; 100 Greenwich Ave., Greenwich, Conn. 06830, or call (203) 869-9090. The next application deadline is mid-July for anytime through September. Locally, Anita Kempers: (703) 444-9306.

AuPair Homestay USA, under the auspices of the Experiment in International Living, places au pairs on the East Coast. For more information write: AuPair Homestay USA, Experiment in International Living, 1522 K St. NW, Suite 1100, Washington, D.C. 20005, or call 371-9410. Application deadline for the Aug. 25 or Sept. 8 groups of au pairs is Monday, July 1.

According to Kratovil, a decision on whether the programs will receive permanent program status will be made in September.

The $2,500 fee, which averages $155 a week, covers all expenses, including travel, pocket money, $100 weekly salary, medical insurance, counseling services, social activities, an orientation program and cultural events for the au pair.