Following this morning's announcement that it would be launching public betas for both iOS 10 and macOS Sierra, Apple has now released iOS 10 for members of the public beta testing program.
Users interested in testing out iOS 10 should visit Apple's Beta Software Program website for more details and to register for the program. Once accepted into the program, users will be able to download a profile to install on their iOS devices that will enable them to receive the iOS 10 public beta. Make sure you first delete any iOS 9 public beta profiles you have installed and ensure you have a full, encrypted backup of your iOS 9.x device before upgrading in case you need to roll back from iOS 10.