"With Windows Vista set for consumer release next month, millions of desktops will soon come with support for Microsoft's new XML-based XPS document exchange format built in. In an effort to preempt this move, Adobe is now testing a set of XML extensions to its own PDF document format. The new format, called "Mars," is supported by a plugin that works with existing copies of Adobe Acrobat 8 (both the professional document creation versions and the free Reader)."Read more here.