The ROCKVILLE CENTRE SCHOOL DISTRICT, located on the south shore of Long Island in Nassau County, New York, is seeking a Superintendent of Schools.     The 3,600 students in the Rockville Centre School District are enrolled in 5 elementary schools, 1 middle school and 1 high school.  The district, which serves a very diversified student body, has a long tradition of high-achieving students and a community that is very supportive of the school district and its students.  Stakeholders are committed to excellence, to a student-centered philosophy, and to enhancing an already successful school district and community.   The Incorporated Village of Rockville Centre is located approximately twenty miles from New York City.  It is a thriving community with a variety