XPS stands for XML Paper Specification – a specification is designed to provide users with a consistent document appearance regardless of where and how the document is viewed, and will be implemented in Windows Vista™. XPS Documents are fixed-format documents described by an XML-based language. XPS Documents also implement features such as digital signatures and Windows Rights Management Server support. The XPS Document package is a compressed ZIP archive, which complies with the Open Packaging Conventions.
Physical contents of an XPS Document package (e.g. pages, resources such as fonts, images, documents) can be viewed with Windows Explorer.
.NET developers can easily create and use XPS documents using Windows Presentation Foundation XPS Document API in the System.Windows.Xps.Serialization namespace.
If you find this topic interesting, check out Bob Watson’s article at http://msdn.microsoft.com/msdnmag/issues/06/01/XMLPaperSpecification/default.aspx, which is the primary source for this post.