Here's How To Install iOS 7 Without Having Registered UDID
iOS 7 Beta 1 is available during this night for owners of iPhone 4, iPhone 4S and iPhone 5 terminals, and you can download it quickly. Following the link below you get a page where you will be able to download the new version of the operating system that is currently available only for the iPhone terminal. It looks like you can install iOS 7 even if you are not registered on behalf of a developer, simply holding down the Option button on Mac or Shift on Windows, combined with pressing Restore from iTunes allowing you to install iOS 7.
If you follow these steps it should work without problems, but it is advisable to make a backup first to save your data. Be aware that you can only restore to iOS 6.1.3 or iOS 6.1.4 if you don’t have an iPhone 4, so make this step very carefully.
1. Download iOS 7 Beta 1 from here.
2. Open iTunes and connect the terminal to the computer.
3. Hold down the Option key (Mac) or Shift (Windows), click Check for Update button of iTunes.
4. Choose the .ipsw file unzipped from the .dmg archive downloaded in step 1.
Everything should be normal and iOS 7 should be installed. If you receive an error and the terminal remains stuck in Recovery Mode, repeat the process. If you still fail to install iOS 7, insert the terminal in DFU Mode and repeat the process.
Do this procedure at your own risk, so you may lose unsaved data or you can get stuck in a version of iOS that you cannot use. iPhoners.org does not assume any responsibility for this procedure, follow it on your own risk.