I just got an autographed copy of the xRM Developer book that David Yack has published. I must say that this is a great resource for Developers and David has packed every ounce of his CRM knowledge into this book.
After you get the book, don't just read the book. If you glance through the pages you'll realize that this is a Developer book with plenty of code snippets. So get the jumpstart framework and code samples from the book website, sit in front of Visual Studio and work with the samples.
I'm sure David would have loved to embed video into many places within the book but unfortunately publishing technology hasn't caught up yet! For that lone reason, it is worth checking out the screencast videos that David is creating for out of the book experiences.
MVP tips within the book are equally valuable. Also remember to follow the blogs of the MVPs to get more tips and tricks.
I'm planning to read from cover to cover and I'd suggest the same for any developer aspiring to work on CRM. I only wish I had the time to do that right away :-)
Many thanks to Dave and Julie for bringing this book to the community.