There is now a book dedicated to MSBuild and Team Foundation Build.  The book is written by Sayed Ibrahim Hashimi and William Bartholomew.  Sayed has written about MSBuild before, both in books and MSDN Magazine articles, and William is a Team System MVP with a lot of experience in customizing the build process in Team Foundation.

If you want to learn more about using build in Team System, you need to get a copy.

Inside the Microsoft® Build Engine: Using MSBuild and Team Foundation Build

Product Description
The build process when code gets assembled to see how and how well it works is a critical step in software development. Developers had few options for customizing the build process before Visual Studio 2005 and Visual Studio 2008, but the Microsoft Build Engine (MSBuild) enables developers to customize each step during a build. MSBuild is extensible and uses an XML file to describe each step, allowing the build master or developer to easily change and augment how projects are built. This book offers hands-on guidance for customizing MSBuild, and provides a cookbook of examples on Web deployment, automated releases, and other essential topics. It also covers Visual Studio Team Foundation Build, the build engine in Visual Studio Team System.