Although it wasn’t mentioned during the presentation, Apple just made iOS 5 GM available to developers. This Golden Master update is as close as it gets to the official release of iOS 5, which will happen on October 12th.
You must use iTunes 10.5 beta 7 to install iOS 5 GM seed on your devices as the iOS 5 GM seed is not available via over-the-air software update feature…
iOS 5 GM is available from the Dev Center for the iPhone, iPad, and iPod touch.