You can set a URI scheme in XCode as @episod mentioned, such as myapplication://, which will redirect you back to your app with the oauth_verifier after it.
I’m doing the same thing, problem I have is twitter doesn’t like it and keeps redirecting me to twitter.com!
EDIT: Scratch that. If you are going to do this method, set the oauth_callback as “whateveryoururlschemeis://[ArbitraryString]”. Some reason Twitter didnt like it without some random text after it.