For those of you who have got an xps email attachment, shared file with .XPS file extension that needs to be printed on the sheet of paper and who are unable to open it using Microsoft Word 2007 needs to download a free windows addin that was officially released by Microsoft.
As you know XPS is an file format released by Microsoft, though there are advantages of using XPS format but the main disadvantage reckons with how to open these xps document. There are no officially available application for opening XPS files, but again, there are addons, extensions for opening XPS file from browser. If you have Windows Word 2007, you can download the XPS Viewer plugin that will integrate the required feature.
With this Microsoft XPS addon, you can the the document or any file to PDF XPS format. This way you can edit the XPS that is to be saved onto your hard disk. You can also save the file to PDF format (XPS to PDF) and open up xps files using browser addons.

The add-in is for exporting word doc out to PDF and XPS, not for reading them in.
http://www.microsoft.com/downloads/details.aspx...
IE8 (probably IE7) have a XML add-on that can read the XPS.