This is a VERY good book for understanding usage of OpenCV and eventually Emgu CV. it provides you with the deal behind the coding. This book tells you about
1.How Digital Image Processing and Computer Vision stuff is implemented
2.Why it is done like that, i.e. the logic and concept behind that implementation
3.The code ! YES! but its in C++ (or C) so you .NET folks need to look up the internet and you'll get things once you have the lead :) i did!
I will be referring to the content in this book now and then in order for you understand some things.