I realize that iOS 7 is not out yet and should not be discussed but I could not find the answer to this question anywhere and iOS 7 comes out in a few days.
I submitted
I just came across the solution here. Anyone with this problem refer to this following post!
iOS 7 App Icons, Launch images And Naming Convention While Keeping iOS 6 Icons
Here is online tool, Icons Master, which will create about AppIcon.appiconset folde, take care how icons should be big naming convection as well.
It doesn't matter what you name the file as long as you hook it up correctly in Targets General Tab. You just click the Folder icon and select the file you want to use. The naming convention only really mattered because that was what was in the info.plist by default for a new project.
And the Targets General Tab realy just sets values in the app's info.plist
Note: I have a build setting ICON_SUFFIX = "Beta" so my beta release via TestFlight has a different bundle ID and Icon so it sits along side my app store version and doesn't over write it.
You can also use one asset catalog to organise your icon images, it's quite easy.If there is one image asset catalog, you use that one, otherwise you can new one. then select Use Asset Catalog in the App Icons part of General tab, you need to prepare the following image size and just drag the images to the corresponding location.
The icon sizes for iPhone and iPad for iOS 5~7 screenshot is as below:
or download it here