Sixty years ago, distance education probably involved a pen, paper, and secretarial classes conducted via snail mail. Today, students in ever-increasing numbers are more likely to link to the Internet to learn how to conjugate French verbs or dissect frogs in Advanced Placement courses, according to a new landmark study from the U. S. Department of Education (www.ed.gov). Nearly three-quarters of all public school districts plan to expand their distance-learning classes, says the study, titled "Distance Education Courses for Public Elementary and Secondary Students." Still more distance-learning courses are offered in dual enrollment programs, in which high schools students take classes offered by colleges and universities.