How to activate without contract:
1. Put in your O2/AT&T official iPhone SIM.
2. Click update and update to 2.0
3. Go through the registration process.
4. It won't ask for contract details. It will ask to accept T&C's then it will ask for Apple ID.
Still locked though! You can use any SIM card from your official carrier though (Pay as you go or whatever!)
Found out by me :D
Tested by about 5 people on IRC..