An email has been doing the rounds with US press, it's from Kojima Productions and they're teasing something which seemingly will arrive this Friday.
The email was subject titled "T -3 days" and pointed to a Kojima webpage, but it doesn't exist quite yet. It could be anything at this point, even just a glimpse of something for E3.
The website it linked to is, but right now it 404s. Guess we'll have to wait.