Tung,
It looks like focusingscreen.com already has a kit ready to go but it's expensive. Twice the cost of the unmodified Canon screen but you get a little tool and some stuff to assist with the mod.
FYI, the screen in my D3 is a Canon Ec-A. They have others as well but the A screen is the one I prefer, personally.
The screens from the Nikon F6 would fit also and need less modification but the grit of the groundglass is not as coarse so the scattering angle is very low with respect to the VF exit pupil and as a result, you can't get the perfect sharp focus as easily as with a coarser screen like Canon makes. Nikon still adheres to the belief that everyone uses f/2.8 or slower zooms on their digital cameras!
There are a bunch of DIY tutorials online about modifying the Canon screens to fit the Nikons. It's not a hard job but it takes a bit of patience and some fit/refit trial and error the first time.
Good luck!
Phil Forrest