Air for iOS iAd

Use this library. It's very easy to use it.
http://code.google.com/p/iad-air-ios/

Initialize iAd
AdBanner.adView.startShowingAds(AdBannerPosition.BOTTOM,false);

Show iAd
AdBanner.adView.visible = true;

Hide iAd
AdBanner.adView.visible = false;