The cross-compiling is fairly simpler now that rustup.rs is in beta (http://blog.rust-lang.org/2016/05/13/rustup.html) however it is still a very interesting and well done series of articles.

Part 2: https://www.bignerdranch.com/blog/building-an-ios-app-in-rust-part-2/

Part 3: https://www.bignerdranch.com/blog/building-an-ios-app-in-rust-part-3/

Part 4: https://www.bignerdranch.com/blog/building-an-ios-app-in-rust-part-4/