Don't know if you'll find what you're looking for, but the description of how to take that big piece of can be found here:
http://home.us.net/~stimpy/xterra/misc/defrost.txt

But before you do, check that the rattle isn't from the most common "dash" rattle complaint cause to date, the cruise control cable that runs across the top of the engine at the back of the engine bay. It rattles inside the plastic guides. Secure it to the guide and see if that doesn't fix it.

Brent

[This message has been edited by OffroadX (edited January 04, 2001).]