Summary: You can now install the GM build of iOS 5 now, even if you are not a developer.
iOS 5 Gold Master build was released yesterday at Apple’s Let’s talk iPhone event by Scott Forestall. This is the final build of iOS 5 from Apple and the iOS 5 is expected to be released on October 12th as a free upgrade to all the active devices that are supported by Apple.
Apple always restricts the GM build to only the developers. But now, it looks like it can be used by the non-devs too to test the build. This is just that your device’s UDID is not checked. However, the IPSW is not available to the public, but is available on major file sharing websites.
You will need iTunes 5 beta 9 to install iOS 5 GM on your device. The GM does not have a OTA from iOS 5 beta 7. I cannot provide the IPSW for you, since I respect Apple and you also need to understand that Apple is just preventing your device from undergoing bugs and preventing you from incurring damage.
Anyways, the iOS 5 will be available on iTunes on October 12th. So, don’t pirate, just wait for some days and you’ll be on iOS 5.