Replacing front and back cover on the BB 8700C
 

How hard or easy is it...What tools do I need? What exactly do I need to do?

I posted this on your other thread that mentioned the housing issue:
The housing, I do believe it is easy to take off the old one and put a new one on.

There are threads here and there as to how someone did theres, but here is a link that was floating around the forums:
RIM Blackberry Forums - Pinstack.com - Free Blackberry Downloads - Device Photos

You have to register to download it, but it gives you step by step pictures of how it is assembled, so one can say you can figure out how to take it apar