So apparently Wizards is pulling all PDF sales, citing piracy.
I have no doubt that selling legal PDF versions makes it easier for some people to pirate. I also have no doubt that people were pirating anyway, and that this won't actually stop them, but only means that anyone who wants a digital copy of the references (in many cases, far more useful than the hardcopy) cannot get it legally. Which is dumb.
Conspiracy theorists suggest that this is all part of a master plan to make their products available online via subscription to their site and their site alone (also, to only offer 4e in this way). I'm dubious, because that plan actually sounds logical. The Compendium they currently offer on their site is not quite that useful yet, but with some upgrades, it could be.
This is also a good time to promote GURPS.