- No, there is no way to read SMS messages. Apple is very strict on this due to privacy concerns.
- Log in to the developers portal and click App Store Review Guidelines.
Nowhere in the guidelines does it specify that you can't access the SMSes. But you can only access if you use private methods which is not allowed and will get your app rejected.
You can only access data for which Apple supplies a documented API. You can not access files outside of the Sandbox of your App unless Apple provides an API for it.