How to get ios7 for my iPhone 5?

I read it doesn't come out until the fall. I've also noticed some people are already getting it. How can I get it?

If you register as a developer with apple then you can download the beta versions for your iphone. However there's a one time cost of $99, apple makes you do this if you want to publish an app in the app store
if you do some google searching I think there might be some ways to get it free, but it could mess up your phone and it may void the warranty.use at your own risk