Free online computer courses from top ranked universities like MIT, Stanford and Harvard are readily accessible via sites like edx.org. While there is no official rating for the courses available, many of the universities offering these free classes are the most prestigious in the world.
In recent years, MOOCs (massive open online courses) have exploded in popularity. Top ranked universities from across the world offer free courseware for any person able to access the Internet. Since their inception, the number of MOOCs available has increased, and due to a larger demand, the overall quality and content provided has improved as well.
One of the most popular online computer courses available is Harvard University's "Introduction to Computer Science" course. The lectures, coursework, quizzes and exams are all equivalent to those taken by students enrolled at Harvard University. The class is taught by an actual Harvard instructor, so the lesson material available online is of the exact quality received at university.
Another widely popular computer course is MIT's "Introduction to Computer Science and Programming." Much like the Harvard course, MIT's version is easily accessible via the MIT open courseware site.
As all that is required to enroll in these MOOCs is an Internet connection, it is worthwhile to try out and compare a few of the different courses available before committing the time required to finish.