Gil Azar has written a Preview Handler wrapper for Outlook 2007 under Windows XP that gives it the ability to preview all sorts of types of files. Specifically, you’ll be able to run all these filetypes right within an Outlook 2007 preview pane or message window:
The last group, in italics, is made possible through wrappers that sometimes require the installation of seperate preview handlers.
Outlook 2007 in Windows XP can’t handle the preview handlers currently available due to security differences between Windows Vista and Windows XP regarding managed code. Read more about it here.