If you not developer and already register your iDevice (iPhone, iPad, iPod Touch) UDID you can upgraded too. Follow this step
- Download iOS 5 GM (Many version and Device)
- Backup your data into your PC/Mac or using iCloud (Apple Recommend using iCloud)
- Connect your iPhone/iPad/iPod Touch into your Mac/Windows with iTunes 10.5 Beta 7 or newer installed
- On your iPhone/iPad/iPod Touch in iTunes click restore with hold option button and choose your downloaded iOS 5 GM ipsw
- Follow the step until it done.
- You will be prompted that your iPhone/iPad/iPod Touch was ready, you can choose fresh phone or restore from you backup
- That’s it, now you have successfully installed iOS 5 GM
If you have any question about this step, leave comment below.