This book is a gift from the Windows Phone 7 team at Microsoft to the programming community, and I am proud to have been a part of it. Within the pages that follow, I show you the basics of writing applications for Windows Phone 7 using the C# programming language with the Silverlight and XNA 2D frameworks. For more information, check out this page : http://blogs.msdn.com/b/microsoft_press/archive/2010/10/28/free-ebook-programming-windows-phone-7-by-charles-petzold.aspx
You can download a PDF here (12.5 MB).
You can download an XPS here (26.7 MB).
And you can download the ebook’s sample code here (5.03 MB).