Using oauth for creating twitter application in iphone

Question

I am creating a twitter application in iphone using oauth. But my application request for:

oauth_consumer_key,
oauth_signature_method,
oauth_signature,
oauth_timestamp,
oauth_nonce,
oauth_version,
oauth_callback,

Please anyone help me how to create all these keys for my application. In my twitter account xauth is disabled by default. So, how can I enable it in my application?