Geez... the original article containing the rumor, which was about the iPhone, was dated July 13. It was repeated in another article three days later. Meanwhile, iOS 6 is only at beta 4. So, no iPhone 5 announcement on August 7. An iMac announcement? Maybe, but doubtful, more like end of August or September, and no keynote event.
A "reliable anonymous" source told me September at the earliest.
I think you mean beta 3.
Yup, hit submit too fast!
Sorry for the late response. Here is the link: http://www.macmania.at/hardware/konnte-am-7-august-hardware-erscheinen/
Sorry, but only in german. They mean that there is the possibility to see new hardware on the 7th of August...