Now that the first beta of iOS 7 is finally in the hands of developers, users are wondering where to find the updated firmware. Here are all the formal links, but be careful what you do.
This first release, number 11A4372q, comes to a small number of devices: iPhone 5, iPhone 4S, iPhone 4 and iPod touch fifth generation, and together with the latter, Apple has also released new Beta for Apple TV, a Beta of the app Find My iPhone, as well as the first build the Xcode developer Preview 5.
via Download ios 7 beta direct link