This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
I think XML Bible is the best guide for this exam. and that's what i am referring to. There is also good site www.xfront.com. Which has good collection of XML schema slides and great exercises like creating schema and validating. It also supplies a tool which can be used for validating schemas.
I am also using Whizlab's Simulator which is also a great tool. and IBM tutorials.