Introduction to implementing neural networks

There are many books about the theory and science behind machine learning and neural networks, but there aren't many books that talk about implementation. This book walks through what it takes to implement, in the C programming language, a simple network that learns the XOR function.

[Note: I'm struggling getting the formatting of the source code in the book right; I'll keep the cost of the book at zero for as long as I can until I figure out how to resolve this issue]