Several sites (Yooph, AppleInsider) have posted an image found briefly on the Apple Australia iPod Touch page which listed June 27th as the release date for the iTunes App Store. The image was quickly pulled, however, and is unlikely to mean anything.
During the 2008 WWDC keynote speech, Jobs specifically said that the 2.0 Firmware would be delivered in "early July". And the iTunes App Store is a major feature of the 2.0 Firmware. We suspect that June 27th was a previously planned 2.0 Firmware launch date that never materialized. In fact, whispers from WWDC indicate that Apple is still racing to finalize the iTunes App Store, so Apple themsevles may not yet know the exact date of its launch.