I have gone through two sources of material: The virtual academy and the book from Microsoft press. Addition to these two sources there are the whole MSDN which also have all info you need. To see which links corresponds to what to learn see my colleagues blog post here.
Microsoft Virtual Academy
This course was shot during one day and split into eight sections. Each sections has a dedicated area that are focused on. The shows host Jerry Nixon and Daren May are very good and know their business. One things which I found nice is that the show is shot in one piece and the small mistakes Jerry Nixon and Daren May does are all in there. Even experts do minor error which is nice to find out.
Now to the content of the videos. I found the content good but not going in depth. And if you have used windows 8 and written some XAML programs before you can skip the first three episodes due it covers the basic of these subjects. But even if the content is not going in depth it is a good quick way to get started with development for and see what possibilities there are with windows 8 apps.
Microsoft press book
Written by Indrajit Chakrabarty this book has a nice language and layout. There are five chapter and each chapter are divided in four or five parts. Each part is about 10 to 20 pages which I think is a nice size. The book includes for each chapter a summary, thought experiments where you have too do some own thinking and some questions so you have the opportunity to test what you have just read. If the virtual academy didn´t go in depth this book does. Of course it can’t cover all aspects of windows 8 development (there are after all a exam 70-485 too) but it goes though all the basics in a nice pace and difficult level. One thing I found that was not in the book was labs with exercises. In previous Microsoft press books I have found these labs a good way of getting some code experience. You can always do your own labs and I even recommend that you do, I believe you should at least write some code in all the areas to get the feel of how its done. But even if there are no labs in the book there are a lot of code which shows you how you can implement the different functions.
If I have to choose only one source I would have too choose the book because it does go more in depth of the subjects. Now luckily I don´t have too choose and can go through them both. I saw the videos first and then read the book which I think was a good way. The videos gives a nice overview and the book goes deeper but the do combine well and I find repetition a good way to make knowledge stick in my head.
Do I recommend this book and video series? Yes I do. I think it goes though all the basics which you need to build you own apps. There are of course a lot of books which cover windows 8 development but if you aiming to get certified this book covers all that you need to know. The videos gives you a nice overview and a good start with your study towards the exam.
Now it has come to my attention that there is a new updated exam coming up now in December 2013, this covers the news in windows 8.1 and visual studio 2013. I know that Jerry Nixon and Daren May has shot a new set of videos to cover that exam so see that instead of the old one when it is published. But I do think it will be some time before a new Microsoft press book will be released. Do keep in mind that most code is the same in windows 8 and 8.1 so I do think it has a lot of value to read the book anyway. Just check what has changed and skip those few parts and get that knowledge from example MSDN.
Edit: I have now passed the exam so the study material worked for me