Ben on the XPS and OPC APIs.
The content team has published Windows 7 SDK documentation for some of the Win32 APIs in the Windows 7 beta. Of particular interest: Packaging XPS Documents XPS Digital Signatures Direct2D DirectWrite Although I’m off to try out the sensor API… Enjoy
MSDN provides details of isXPS, a tool that tests conformance of files with XPS and OPC. You can find details of isXPS on MSDN, but where is the tool itself? isXPS is included as part of the Windows SDK. Once installed you’ll find it at: <Program Files>\Microsoft SDKs\Windows\v6.0\bin\IsXps.exe