You can down load a free eBook The Art of XSD - SQL Server XML Schema Collections By Jacob Sebastian .

From the website

This book will help you learn and use XML Schema collections in SQL Server. Prior knowledge of XSD is not required to start with this book, although any experience with XSD will make your learning process easier. This book starts with the basics of XML schemas and then walks you through everything you need to know in order to build powerful XML schemas in SQL Server.

Here is the link to download