Chris Priestly, Bioware's community coordinator, posted a bit of a tease Tuesday night in the Mass Effect Forums, telling readers "If I were you, I'd be around here at 10am tomorrow."
Of course that bit of hintage lead to seven pages of speculation about some megaton announcement, when it might just be news of downloadable content. My money is on the latter. We'll make sure to post the news here as soon it hits, but I wouldn't be skipping lunch or meetings to wait to see what it is.
Update: News is live, we so called it.