The U.S. Bureau of Labor Statistics estimates that there will be more than two million new tech jobs by 2020. By then, students may not need $250,000 educations to get hired. At its launch in February, Udacity, an online service that offers computer, science, and business courses, had already enrolled 150,000 pupils. Students watch lectures, take automated quizzes, and receive certifications, which can be presented to employers. Free