MIT and Harvard today announced a joint initiative, dubbed edX through which both universities will offer courses for free or nominal cost. Video of their press conference is at the link above.
Currently there is one prototype course in progress which started in March, offered by MITX and paralleling MIT's introductory electrical engineering course 6.002 (Circuits and Electronics). It has exactly the same content that resident MIT students receive. Over 120,000 people worldwide enrolled in the prototype course and last reports were that over 20,000 have been keeping up with the homeworks, online "labs" and midterm.
edX will offer courses under the MITX and HarvardX brands and is a non-profit organization. In the press conference the MIT provost said that while they are non-profit they don't want to become a drain on the budgets of the universities--so perhaps the implication is that ultimately there may a nominal fee for certificates, although right now for 6002x it is totally free.
edX makes the bold goal of reaching 1,000,000,000 people in its effort to educate and also to collect unprecedented data on the learning process and the role of technology to facilitate and improve it.