Free Wifi - but only if the clerk remembers to tell you!
We stayed in a King Corner Suite last night (July 23, 2012) and were advised at check-in that we had free wireless in the room. Yet, when we tried to log-in at the W site, the page required us to pay for the wireless. Since we didn't really need wireless, we didn't continue the registration process. I mentioned this to this desk clerk at check out. He reviewed our bill and commented that the W had not charged us for internet. And that was all he said on that topic. 
So there you have it: according to the desk clerk at the W, wireless is free, as long as you don't use it. 
The hotel itself is lovely and the room was spacious. Overall we enjoyed our stay, thus the 3 star rating. Our last experience in the hotel is however indelibly bad. 
It seems you have to pay for the free wireless if you do use it.
UPDATE
I addressed this issue by email with the GM of the W and received a very prompt and apologetic reply.Apparently, at the wi-fi log in site, we had to first agree to pay for the wi-fi and then to trust that the charge would be removed at check out. For the gracious and prompt reply, I am upgrading my service rating from a 1 to a 3, since an apology (even accompanied by Starwood points) can't change the actions of the staff at the time.