If you have a iOS Developer account you can already now download and install the beta on your iPhone. If not, there are several other ways to get iOS 7 on your iPhone. Just do a Google search on “Install iOS 7 guide“.
NB: Remember to have your UDID ready and activated on your (or a friends) iOS Developer account, before installing iOS 7, otherwise you’ll have to downgrade to iOS 6 – find out how here.
I just installed iOS 7 on my iPhone 5 and so far it’s working flawlessly. Here are some screenshots.