This is the course that got me interested in quadcopters https://www.edx.org/course/autonomous-navigation-flying-robots-tumx-autonavx#.VI7tRKSUf3o It is an archived course now which means that you cannot get a certificate but you can still see the course content and do the exercises. This covers several useful topics ranging from the basics of quadcopter flight to PID tuning to state estimation and filtering noisy GPS readings. This ought to be helpful for people who are just getting into quadcopters as well as experienced people building their own flight control boards. The prerequisites for this course are listed as:
A solid background in linear algebra and 3D geometry.
Some knowledge of Python programming (especially the NumPy library)
I did not have much knowledge of either when I did the course but I learnt Python here: http://www.codecademy.com/ and passed the course by debugging code that I got on the course forum  (plus, the lowest week's score is not counted). I have started going over the course material again in the hope of actually understanding this time and so I thought I should share it here in the hope that it benefits some others

This is course is being run again. Those interested can sign up here