well, what do you know?!? I just clicked on the "updates..." and it found the JB update. downloading it now (in Baysides, NY)
I have the Nexus 7 so I already have (and used to 4.2). For those of you who are expecting *great* differences from ICS, you're going to be disappointed. JB is smoother and more intuitive to use, but it's not a drastic change from ICS.
have fun everyone.