I'll go ahead and confess, I'm a sucker for viral marketing. And I know at least some of you have seen Transformers and will know right away what I'm talking about, but for those who haven't seen it, take a minute to watch the trailer below. I'll wait.
And that's it... No name, just a JJ Abrams' producer credit.
In addition to being easily hooked by creative (and sometimes not so creative) marketing, I'm also a fan of BIG monster movies.
A little investigating and a quick Wikipedia search turned up the working title "Cloverfield", but other than a cast listing, that's about all there officially is.
The most popular speculation is, of course, that this is some kind of new arthouse Godzilla, but Toho's (supposedly) retired big-G's franchise until 2010 or something, so who knows... personally, I kind of doubt it, but it could be cool.
Other speculation (which you can read about further at the Wikipedia entry) includes a Cthulu-themed monster, something called The Parasite, a new Rhodan, or a Lost tie-in movie.
Entertainment Weekly site reveals the one sheet...
www.slusho.jp, a tie-in site that has a lot of clues...
The "official" site...