There has been a lot of rumors lately concerning Apple's event and the actual date, but now it looks like September 12th is currently the strongest rumor around.
According to a Reuters report and its anonymous source, as well as an AllThingsD report, the event should take place in the week of September 10th, or precisely, September 12th. Of course, Reuters claims that the actual date could shift. The iPhone 5 announcement is most likely the biggest thing around and according to some recent rumors, Apple is expected to bring a device that has a larger 4-inch screen, thinner body and a handful of other tweaks.
As it is always the case with Apple, things tend to change quickly and nothing is certain until invites start to roll out, but we are a good month away from it.