What is it with Apple and September when it comes to music?
For that last several years, Apple has used an early September media event to introduce some sort of new music service, feature or device, and if the rumors swirling about today are true, this year will be no different. Japanese Apple site Kodawarisan  pegs Sept. 7 as the date, citing knowledgeable sources.
As for what is expected at the event, there are two main buckets. First is the introduction of the iPhone 5. Apple usually makes iPhone reveals during the summer, and did not do so yet this year. There's also a slight gurgling of talk about a possible iCloud iPhone, which is said to be a smaller, cheaper phone with virtually no storage capacity and fully reliant on Apple's upcoming iCloud service to access content. The rumors also point to mobile operators offering the phone for free, with a contract (using the rationale that a cloud-reliant device would run up enough in network charges to make the carrier subsidy worthwhile).
If these rumors are true, the phones won't likely be immediately available. Any phone sold in the U.S. has to pass FCC approval first, and submitting phone specs to the FCC is a public process. So Apple tends to hold events announcing all the details first in a forum that it can control.
And with all these iCloud-focused devices, it's possible that a Sept. 7 event could also mark the official launch of the iCloud service. The details of iCloud  were made known earlier this year, but the service itself has not yet gone live. Next month could mark that milestone.