In what may be the most authoritative confirmation yet of rumors that have been floating around for months, a Bloomberg report late Tuesday cited two unnamed people familiar with Apple’s (AAPL) product release plans to say:

• Apple plans to release the successor to the iPhone 4 in September
• It will run the same, more powerful, A5 chip that drives the iPad 2
• It will have an 8-megapixel camera (up from 5 megapixels in the iPhone 4)
• The release was delayed until September to coincide with the launch of iOS 5, the new operating system introduced to developers on June 6

Bloomberg’s story was published more than 12 hours after the Boy Genius Report, a weblog with unusually good sources in the cellphone industry, reported that Apple was planning a “radical new case design” for the next iPhone and that its release might come earlier than expected, perhaps in late August.

It’s not clear whether the iPhone rumors had anything to do with the performance of Apple’s shares, which reversed a downward trend and shot up $9.98 (3.17%) Tuesday to close at $325.30. Wall Street traders aren’t known to read the Boy Genius Report and Bloomberg’s piece was posted too late to affect trading.