It's rare that I'm the one to state the obvious but what the heck's up with Windows Vista & Office 2007 not providing a Preview Handler for the .XPS format? Isn't a .XPS Handler obvious? Shouldn't I be able to view a .XPS file in the Outlook Preview Window in the same way I view a .DOCX file or a .PDF file if I have the right Preview Handler installed? Or do the same in an Windows Vista Explorer window when using the Preview feature? (See picture for how to turn this on) This in my opinion is a gross oversight and I'm curious as to why we left one out.

Fortunately, the folks in MSDN [have] provided all the tools necessary to cobble together your own solution. Stephen Toub & Ryan Gregg already wrote a bunch of Preview Handler code in .NET a month ago and provided it as a learning kit in MSDN Magazine to enable other people to write their own Preview Handlers. And they provided an installable .MSI file which will install not only an XML Preview Handler (to view .XML files cleanly within Outlook/Windows Vista Preview) but also a XPS Preview Handler as well based on the same code.