While rumors about the features of the next-generation iPhone 5 have mostly bordered on the unlikely or bizarre, the latest speculation about the release of the most-awaited Apple smartphone has remained constant for last few weeks.

Reports suggest that the Cupertino tech giant will be unveiling its phone on Sept. 12 and pre-order for the phone will begin on the same day.

According to Rene Ritchie, the editor of iMore and one of the most reliable sources when it comes to iPhone information, Apple will start taking pre-orders of the iPhone 5, "at least in the US," from Sept. 12, while the actual date of release will be Friday, September 21. Ritchie has received his info from "sources that have provided iMore with accurate iPhone related launch dates in the past."

Regarding the international launch of the iPhone, iMore informs that "the second wave of iPhone launches, the ones in international markets, will begin in the first week of October, likely October 5."

Additionally, several retailers and carriers like Best Buy, Target, and Sprint have already slashed the price of iPhone 4S. The price slash fuels speculations that the release of the fabled iPhone 5 is nearing.  

BGR reported that AT&T was planning to launch Apple's upcoming iPhone in the third or fourth week of September. Reliable sources told BGR that the launch had been scheduled "with an all-hands-on-deck policy in place for employees that will extend through to the middle of October."

"A second AT&T source confirms that a large training event for regional employees has been rescheduled from the first week of October due to a conflict with a 'huge announcement'," BGR reported.

Asymco analyst Horace Dediu predicted that, Apple's next-generation iPhone 5 will have cumulative sales figure of more than 263 million units. Dediu also mentioned that the Cupertino tech giant will "easily" sell at least 250 million units of its next-generation iPhone if the company keeps the device in production, as long as it did for the iPhone 3GS.