I know my reply here will be shot down and angered but the message needs to get across.
It's $99/year for an Apple Developer license which gives you access to the Apple Developer portal. Every year, around the time that beta's are launched users try and find ways around paying this fee so that they can try an iOS developer beta.
Then, they come on MacRumors and post threads about how it's buggy, apps they use daily do not work and they flood the forums with threads that mostly lack common sense.
What all of you need to understand is Apple doesn't handle beta software like some of you think they should. It's not "beta" software, it's DEVELOPER BETA software. The beta software they release is meant for developers only. This is why they hide the software behind a PAID PORTAL.
By downloading the .ipsw from a third party you are breaking the law and doing something illegal. Nothing more needs to be said on that. Installing it is not the problem, the problem is 3rd party sites hosting the software that is legally bound by contract behind a paid portal.
Why does Apple do this? Because DEVELOPERS need access to early versions of the software so that on launch, their apps are already ready to go for you to use (Think Facebook, Twitter, etc).
And finally, no one on here is that stupid to believe the majority of you are actually submitting bugs. Why? Because you're on here posting silly threads about how your favourite apps don't work or how you hate the beta because it's unstable. Don't feed me that line. If you were really helping and submitting bugs, you wouldn't need to post it on MacRumors as you'd have already used Apple's Feedback system (the only place that your "opinion" actually matters and can do some good).
By installing this software as a joy ride to play with you are doing absolutely no good in the development of iOS. If you really want to contribute to the development of iOS 7, wait until you're able to install iOS 7.0 in a legal, public release way and submit bugs. Apple's iOS X.0 launches are the REAL BETAS. They're released to the public AND you can submit bug reports and actually do some real good. All those iOS versions after X.0 (Like iOS 7.1, 7.1.2, etc) will be the versions where YOUR BUG REPORTS matter.