I really enjoyed the free "CS193P" course from Stanford with Paul Hegarty. It is not 100% up-to-date but still a good start, covering Xcode/iOS8/Swift:
https://itunes.apple.com/us/course/developing-ios-8-apps-swi...
https://itunes.apple.com/us/course/developing-ios-8-apps-swi...
I started iOS programming about a year ago and it really helped me with grasping how to use Auto Layout in XCode, once you learn that the API is easy to pickup if you have some experience in mobile development.
Swift is a pleasure to use.