Not that I can see they aren't. They will for all other networks bar O2. I would love for someone to prove me wrong as I'd pre order in an instant
They did yesterday on the website when you click the "Upgrade" tab - Just had a look on the site today after reading what you guys put and it doesn't seem to be there ... I ordered over the phone though and the order has been confirmed and I havn't had anything to say it has been cancelled.
I would give them a call they might still be doing it.