Apple posted iOS 7 Beta 1 to developer on June 10th but in order to install on iPhone and iPod touch either you should be a member of Apple’s developer program or your device’s UDID must be registered against a developer account.
In case you want to update your iPhone or iPod touch to iOS 7 without having your iPhone’s UDID registered in a developer account, you can do so easily? In order to install iOS 7 without UDID account you must first download an official copy of iOS 7 (build 11A4372q) IPSW file.
Be sure to download from verified source and it would be good if you can get it from a friend who have already installed it.
Once you have a copy of iOS 7 IPSW in hand, press and hold the Option key (Shift for Windows) and click Update in iTunes. Select the iOS 7 IPSW when prompted to install.
Yes, the process is straightforward and is working fine. Check it out on your device and share your feedback.