Gizmodo claims that the iPhone 2.0 Firmware could hit Golden Master this Friday. The Golden Master version is the final shipping version of a product, which means we could also see the 2.0 Firmware released as soon as this Friday. Gizmodo warns that the date is tentative, but falls in line with Apple's original plans to deliver the 2.0 Firmware by late June. At WWDC, however, Steve Jobs revised the release date to "early July".
The 2.0 Firmware will be available for free for existing iPhone owners and as a $9.99 update for iPod Touch users. The biggest new features of the 2.0 Firmware include Exchange/Enterprise support and 3rd party application support, but Steve Jobs also highlighted a number of additional improvements during the 2008 WWDC keynote. These include: contact search, iWork document support, Office documents (Word, Excel, and now PowerPoint) support, bulk delete & move for messages, scientific calculator, parental controls and additional language support.
Of note, even if the 2.0 Firmware is ready for delivery, we've heard that the App Store is still undergoing active development, so the entire release could be delayed until it is ready.
Update: The story has been updated to suggest that the actual public release won't be until July 11th.