How To Install iOS 6
To install iOS 6 beta, you will need iTunes 10.6.3 as well as the appropriate firmware file for your iDevice. These can be found on our downloads page. We also need your UDID so your iDevice will work with the beta. See our Finding Your UDID page.
After installing iTunes have your iDevice connect via USB so it is visible in the iTunes sidebar. Click on the device name. Now Option + Click the Restore button if on a Mac or Shift + Click the Restore button if on a PC. In the dialog that pops up select the iOS 6 .ipsw you downloaded. Wait for your iDevice to update and enjoy iOS 6!
If you’re worried about losing any data, don’t be! As long as you have a recent backup made you can safely restore to the backup after installing the beta.