Cocoa Touch Netcast (CTN) is a collection of video episodes that introduce you to: Objective-C, XCode and Cocoa Touch.
All you need to follow along is a Mac running 10.8 or latter. The Xcode SDK (Software Development Kit) is free from the App Store and includes an iOS simulator. You can also run your apps on your iOS device if you join the iOS Dev Center ($100US/year)/.
CTN episodes are listed in reverse order; goto the "Introduction" and get started.