To view XPS files, if you do not have Windows Vista or Microsoft.NET Framework 3.0, you can download the Microsoft XML Paper Specification Essentials Pack Version 1.0. The download contains an XPS Reader, very much like the Adobe PDF reader and an XPS Document writer, which allow you to print to XPS files.
There are other goodies in this pack such as:
an XPS IFilter that will help you index XPS files, with Windows Desktop Search for example Windows shell handlers for thumbnail views in Windows Explorer The pack requires Windows 2000, 2003 or XP with the latest service packs and Microsoft Core XML Services 6.0. It’s still a beta, but worth a shot.