of jj abrams secret movie

Mystery Trailer Leaked: Some guy shot this trailer which was shown before the Transformer movie. The title of the movie is still unknown but it is produced by JJ Abrams (Mission Impossible III) and opens 18th Jan 2008. It is so hush hush that the movie is codenamed Cloverfield. [via Trailer-Parking]

IMDB describes the movie

A giant monster movie (currently referred to internally as Cloverfield; the monster itself is referred to as "The Parasite", not to be confused with the film project The Parasyte) that is shot using home video cameras from the point of view of people who are experiencing an attack on New York City.

Update 1: Here's a full analysis of the audio and lines of the mysterious trailer.
Update 2: Cloverfield on CNBC.