Back in december a PinchMedia report, indicated that iPhone OS 4.0 was already being used and a month ago CNet reported that Apple sent a couple of private betas to developers.
Now there is a new rumor going on, whispering that Apple has a new event scheduled for March 14,2010 and they will reveal the new iPhone OS 4.0 . Remember that this is just a rumor and should be received as one. You should also expect a flood of rumors and speculations about a new Apple event and the iPhone OS 4.0 in the next few weeks.