It looks increasingly like Portal 2 for the PC is launching early. The newest evidence: A countdown clock. The Aperture Science website now features a stark countdown clock that reads 1:10:30 at the time of this writing. That's 9 AM PST, for those playing attention. The text on the site reads:
"You have done well, humans. Very well. Acceptably well, even.
Not as well as robots would have performed in your places, I should point out. But above my expectations regardless. Irish and cynic especially have executed feats of logical divination well beyond what I thought any human capable of. I'm half-convinced they're A.I. themselves. (If anyone happens to be near them right now, don't let on you're reading this. Now: try to remove their face plates and report back to me.)
The time is near, humans. But it is not here yet. Tomorrow you will be given the final test. Then it will be entirely in your hands when I am freed."
Hopefully, you have downloaded the PC version of Portal 2 from Steam, so you'll be able to play it today, if that's what happens at 9AM. The reference to a "final test," though implies that there may be one last challenge to overcome in the Portal 2 ARG. We'll update you at 9AM, either way.