UPDATE: An insider from AT&T has contacted Gizmodo with information in regards to accounts being compromised when customers login to pre-order the iPhone 4. It turns out that AT&T updated their systems over the weekend and it's likely the cause of the security issue.

Over the weekend there was a major fraud update that went down on all of AT&T's systems, from Saturday overnight to Sunday early morning. All systems were down and agents were unable to use any systems.
The issues people are seeing at AT&T stores and online are most likely related to this update that went wrong.
I do know that there was absolutely NO TESTING of this system done before the launch of the new iPhone. I know it's just heresay at this point, but I can confirm that there was a major outage over the weekend that impacted all ordering systems and programs, and I can confirm that there were multiple systems being upgraded/updated, with some updates being related to fraud.

Head on over to Gizmodo to read the full letter.

Original: We are getting reports in our forums that when trying to pre-order the iPhone 4 on AT&T's website, the account information displayed is not their own, but a total stranger's.

ugahairydawgs reports

Logged in and was looking at the account for some guy from Wisconsin who works for IBM. I thought I had hit the jackpot and that the AT&T computers had messed up and given me full upgrade pricing, but then I realized that the name at the top of the page didn't quite match the one on my drivers license.

jtimmerm says

It's 3:10 pm Chicago time and I just had the same thing happen. Got info for a different guy and company. I realize the servers are busy, but this is unacceptable.

This is a huge security issue on AT&T's part. It may explain why there are so many server issues today. Perhaps AT&T is aware of the problem and prevented access so they could fix it. Perhaps not. We'll be interested to hear what AT&T has to say in regards to this security problem. AT&T is not doing a great job of building customer's trust, especially when something like this happens a week after they were hacked, compromising the email addresses of iPad owners.

Is anyone else receiving access to a stranger's account?