Possible solution to activation: what worked for me after 24 hrs of waiting

So I was in the same boat as everyone else thats waiting.
Let me describe my account and if it sounds like you, this will probably work for you as well.
I am an existing Cingular customer with an old Cingular plan. I also had a corporate discount which made my account a "business" account.
I went thru the activation and got the "more time is needed" screen everyone is staring at.
I then called the phone # thats listed in the big thread (the iphone activation #) and got them to cancel my activation. I went to the AT&T store and picked up a new sim card. I also called AT&T and switched my plan to a normal AT&T plan and had them remove the corporate discount (since it doesn't work on iPhones anyway) and also made them change the account into an individual account and completely remove all association with a business account.
After all this was finished, I tried to activate again and got an error saying my new plan isn't valid for an iPhone (not verbatim) it listed two #s to calls, 1 is for business customers and 1 is for regular iPhone activation. If you get this message, it means your previous rep that you told to remove the business account failed to do his job. Call the business line(866-907-3484), explain your situation and that you want the "BMG" association removed and you're stuck on it saying you don't have a valid plan for an iPhone. They know the issue, there is no run around with them. They will fix your account and stay on the phone with you as you go past that step, get to the end of your activation and your phone WILL be activated within that 3 minutes.
Getting a new SIM card isn't necessary as long as you cancel the current activation. That is a MUST! You will get an e-mail letting you know your activation is canceled.
Good luck! Wish I wouldve known this information from the beginning it would've saved me a day!

Thank you so much for sharing this. I have tried for 24 hours to get my iPand was told by ATT that there was just no way that my business account could be changed until Monday. I followed your instructions, called the business line(866-907-3484) and got it to work last night.
Thank you again!