I'm wanting to view the CQ Zones in Google Earth, and I understand that a KML file will allow me to do so. Is there a place where I can get a KML file that shows all of the CQ Zones?
There is not any such listing, as the definitions for CQ zones are a bit ambiguous. The official definitions can be found at the CQ Magazine WAZ award definition. Areas like the ocean aren't covered, otherwise it's a fairly simple geography lookup to get the areas defined.
Yes, there is now. This is probably what you want.
This may be helpful. Specifically the link titled "Map of QTH Locators for whole World". I was able to successfully determine my grid square using it and it covers the globe.