Yes, there are a number of colleges now offering classes online for free. In most cases these classes do not count toward degrees, but there is talk of trying to start doing that. In many cases they will give you a certificate for completing the course and in some cases you can apply for continuing education credit. This gives more people an opportunity to update themselves in areas that interest them. Political science and computers have always been a large interest for me (my undergraduate degree was political science).
Classes cover all kinds of subjects. All types of colleges are offering these including Hillsdale in Michigan, Harvard and MIT among others. These classes are often the same as the credit classes taught at the college or at least by the same instructors. www.coursera.com is the clearing house for many of these colleges. You can normally do the work at any time during the week or often they are archived and you can do at a slower pace.
I learned about Hillsdale Collegeís (www.hillsdale.edu) course on the Constitution (101) thru an email from them and I took a course in the spring and got a nice certificate. I am now taking Constitution 201 from them and starting next week a history class on early western civilization history. These are very professionally done. The James Madisonís Montpelier Center for the Constitution offers free classes on the Constitution also at http://learn.montpelier.org
In addition Microsoft has started the Microsoft Virtual Academy (MVA) which has a large number of Microsoft classes available for free. They are available about a number of different types of Microsoft software. I have enrolled there and am talking a class on IT Connectivity and will do an introduction to Server 2012 next. Currently Microsoft keeps a record of you completing the classes but plans to start issuing certificates soon.
You will also see these classes referred to as Massive Open Online Courses or MOOC. The possibilities of what you can take and where is growing daily.