Multiple reports coming out in the last couple of days have confirmed that the new iPhone(s) will be announced on Sep 10th and will be available to ship on the 20th of Sep. This is in line with last year's iPhone 5 timeline; iPhone 5 was announced on Sep 12th 2012 and started shipping out on the 21st of Sep. Also iOS 7 should be available to download on or just a few days before the new iPhone(s) ship(s). Mark your calendars!
Also contrary to a a recent report, 9to5mac has an in depth 'mythbuster' style article on how iPads will not be announced in the same event as the new iPhone(s). Since Apple has not had any major product releases yet, since last fall (2012) and most of its products are due for a refresh, it is going to be a busy and exciting fall.