XPS Annotator is an exclusive standalone XPS Viewer (not hosted in Microsoft Internet Explorer), we adding some features including annotations, document properties, digital signatures, and sidebar for ease of reading.

Main Features :

Allow you to add notes or comments to an XPS documents to flag information or to highlight items of interest for later reference, support for adding text notes, ink notes, and highlight annotations.
Can adding document properties to your XPS documents (creator, identifier, content-type, title, subject, description, keywords, language, category), this feature will help you to manage your XPS documents easily.
Built-in sidebar for ease of reading. The sidebar contains a thumbnails from all pages, you can jumping from one page to another by clicking the thumbnails.
Support security features, such as digital signatures to provide greater document security.
Support for common operations including save-a-copy, print-output, copy-to-clipboard, zoom, and text-search.

Platform: Windows XP, Windows 2003, Windows Vista

System Requirements: Microsoft .NET Framework 3.0 (already installed on Windows Vista)