Just sign in with your iTunes account name and password - from what I've read this works and bypasses any activation process.
Yep, this worked for me, much to my surprise and subsequent joy at having 2.0 working without any problems whatsoever!
I'm running an unlocked and jailbroken phone, but using an O2 PAYG SIM.
Obviously it's now not jailbroken and possibly not unlocked anymore, but it looks like for anyone in the UK using an O2 SIM, contract or otherwise, you're good to go and enjoy!