The free resource I'm about to start utilizing is the MIT (yes, that MIT) Open Courseware programs. It's pretty much all the workbooks from an MIT course, but with no formal exams or accreditation. But for learning something new in your own time, I don't think you can beat it. The Electrical Engineering and Computer Science courses are here - http://ocw.mit.edu/courses/electrical-engineering-and-computer-science/