Maurice,
There is much synergy between the Office tools (Word, Excel, PowerPoint)
most of which is beyond what can be written here, e.g. copy/paste,
graphics, export, import, familiar look and feel, etc. You've asked a
wide open question impossible to really answer without knowing what you
have in mind. Heck, it's all Office and Windows so synergy occurs by
default.
Re XML ... XML is not simple, and Project's XML is complex. I would
guess that it's beyond the skills of novices to do much more than just
let Project use it. I would find it unlikely you need to use it for much
other than perhaps automated integration with other systems. But again,
I don't know what you have in mind. Documentation about Project's XML,
is available on Microsoft web site somewhere (I think).
Project 2007 does an awful lot of things and for novices I would urge
you to learn it instead of finding ways to use the "edges" of the
product to make "improvements". Learn how Project works and how to use
it as tool for managing complex information associated with project
cost/schedul data. Project is a big calculator with a bespoke front-end
with a back-end relational database--all specifically designed for
project cost/schedule data.
--rms
www.rmschneider.com