This is a simple UIViewController that performs the Instagram authentication steps on iOS.
Instagram-Auth-iOS might be useful for you if you're building an iOS app that requires Instagram authentication to access the API. This example presents a UIViewController for the user to use for login, and does the authentication dance with Instagram to retrieve an access token that may be used for further API requests (retrieving the user timeline, accessing likes, comments, etc.)
Note that in order to use this, you will need to obtain a client ID and secret for your app from Instagram