Andrew Ng, Chief Scientist at Baidu and associate professor at Harvard University gives an online lecture on Deep Learning. This is a very innovative media form and gives great insights into Deep Learning.
Michael Nielsen is a scientist and programmer, who published several works on quantum physics and quantum computers. Quantum computers could be an interesting hardware solution in the future to accelerate the training process and calculation of the output Deep Learning algorithms. This is a free publication, which gives an introduction to Deep Learning.