Sorry my fellow North Carolinian, but J. J. Abrams himself confirmed that it was not Godzilla, but a totally new monster that he wanted to create for this new movie. He said so back in August or so.
For any further discussion on "Cloverfield", there's a hefty thread going on over in the Sci-Fi forum:
http://www.clubtokyo.org/discuss/viewto ... 12&start=0