MIT publishes virtually all of its course materials online for free.   http://ocw.mit.edu/index.htm  You can take hundreds of college courses completely free, in your own time. This is the Massachusetts Institute of Technology- one of the premier technical universities in the world – offering courses online because they want more people educated.  The list of courses is here  http://ocw.mit.edu/courses/index.htm  Something every one should know and use.  Please share this valuable resource with everyone you know.