In addition to announcing the next-generation iPhone at a media event on September 10th, it is likely that Apple will seed the iOS 7 golden master to developers for testing. While the GM version will still be considered pre-release software, it should be virtually identical to the public-facing version that is released in the ensuing weeks.
Ahead of that release, a sixth beta of iOS 7 is expected to be released. There is a slight chance that iOS 7 beta 6 could drop at some point today, but it is more likely to be seeded on August 19th. Apple had been sticking to a two-week release cycle for its iOS 7 betas, until unexpected Developer Center downtime delayed that schedule.