iMore has learned that Apple is planning to debut the new iPhone at a special event on Wednesday, September 12, 2012, with the release date to follow 9 days later on Friday, September 21. This information comes from sources who have proven accurate in the past.
The iPad mini will be announced at the same September 12 event, as will the new iPod nano. We haven’t heard a release date for the iPad mini yet, but it could be the same as the iPhone 5. It seems likely the new iPod touch will make an appearance on September 12 as well, though we haven’t heard any specific information about that yet either.
Last year, the iPhone 4S was announced on Tuesday, October 4, 2011, and released 10 days later on October 14. The event included minor updates to the iPod line, notably a white iPod touch 4. This year, the iPad 3 was announced on Wednesday, March 7, 2012, and released 9 days later on March 16. The event included a 1080p Apple TV.
Source: iMore – Apple iPhone 5 and iPad mini event planned for September 12, iPhone 5 release date for September 21
And, one more rumor from 9to5 Mac about a new iPad:
Finally and probably most controversial, Apple will be updating its full sized iPad line with a thinner design less than a year after release. The new, new iPad design will be tweaked with a new back side mic and a less hot thinner design.