Digital school bells will ring this week on MIT's much-anticipated OpenCourseWare Web site when it starts offering free content from dozens of MIT courses. The goal: to share content with researchers, educators, and people who can't afford tuition.

These first courses cover subjects such as software engineering and economics. You can't earn an MIT degree via OpenCourseWare, but you can access professors' lecture notes and other content from earlier semesters.

MIT says all of its courses are due to go online within about seven years.