Microsoft have an add-in that will allow you to save your documents or excel files into XPS format. This is only available for Microsoft Office 2007.
This download allows you to export and save to the XPS format in eight 2007 Microsoft Office programs. It also allows you to send files as e-mail attachments in the XPS format in a subset of these programs. Specific features vary by program.
This Microsoft Save as XPS Add-in for 2007 Microsoft Office programs supplements and is subject to the license terms for the 2007 Microsoft Office system software. You may not use this supplement if you do not have a license for the software.