Anyone can pay $99 to be a Developer and then download the iOS 7 beta. HOWEVER, note, you will have to sign a very restrictive NDA (Non-Disclosure Agreement), and Apple takes their NDA's very seriously.
You should also note, that there have been lots of "I installed iOS 7 and not my (your device here) does not work. Help!" posts. iOS 7 is beta because it is not ready for prime time. It can make your device non-functional. It can loose or corrupt your data. It should ONLY be used to test the environment with non-critical data so that any loss will not impact you.
But if that is the environment you would like to have, then go to the developer.apple.com web page and sign up to be a paid developer.