According to a customer care rep for AT&T, the iPhone 5 (if that’s in fact what it will be called), will not be released in the typical June or July time frame. According to an iPhone customer who contacted AT&T about his upgrade eligibility, the AT&T rep is quoted as responding to his request with:
Apple has informed us that they do not plan to release the iPhone in the June to July timeframe, though there will be a newer version in the future. Unfortunately, we have not been given a release time for the new phone. We will release this information on our website when it is available to us.