File format for submitting iPhone app in App Store

When I am building my app,Xcode generates it in .app format. Usually when I install app from AppStore they are in .ipa format. How does this format get generated? Wil开发者_运维技巧l it be done by guys at AppStore while reviewing app or what? In which format should I compress my .app file?

Thanks

An .ipa file is simply a zipped archive of a .app bundle. Previously, you would simply zip up the compiled application bundle (by right-clicking on it and choosing Compress "xxx.app") before submission, but newer versions of Xcode now do this for you with their Build and Archive or Archive options.

In fact, you might be able to learn things by unzipping other application .ipa files you get via the App Store and inspecting their contents (like Info.plist settings or bundled resources). I know I have.