The method of modifying the XML data so that it is readable in something, like Internet Explorer, you need to use XSLT, Extensible Style Sheets (or CSS, Cascading Style Sheets).
These files, are basically what you have seen before, something that would be in vBulletin is cp.css, or <style> tags at the top of each generated page.
With CSS, is where you define what the parser should do to each of the tags, for example, you specify that each author(with <author> around it) be centred and red.
XSLT is slightly different, where you define the layout of a page, therefore you can have the system that MAS*MIND has done, where authorid is after author, and still use authorid before author.
Its a bit hard to grasp the concept of it, and best method is actually Books