I have download Flash Builder 4.5.
When I install it, I also check 'Air for Apple iOS support' to install it too.
But when I create a new Flex Mobile Application, at the second page, I can chose the Platform Target be I just have Android and not iOS.
What do I have to do to create a iOS application?
You need to create an Actionscript project to see iOS in target application list.
When you create a mxml mobile project you'll see only android.