Apple has released the promised iOS 4.0.1 update that fixes the way the signal bars are displayed. You can download it now from iTunes.
Apple positioned this update addressing the antenna issue in some form. In the meantime Apple has scheduled an iPhone 4 press conference for today and reports appeared that there is another iPhone software update in the cards that directly is addressing the iPhone 4 Antenna death grip issue. The new signal bar update has already been tested in the upcoming OS 4.1 beta and did not provide any fix for the antenna issue.
Back to the iOS 4.0.1 update. I just installed it. The release note says that this update improves the formula to determine how many bars of signal strength to display and applies to iPhone 3G, iPhone 3GS and iPhone 4.
By the way the rumor from Greece was indeed true. iOS 4.0.1 was released on July 15th.
We will learn more from Apple about the Antenna issue today at the iPhone 4 press conference at 10am PCT.