A quick addition to Duncan C's original description vis-รก-vie IB behavior. He writes: "It's trivial to make hyperlinks clickable in a UITextView. You just set the "detect links" checkbox on the view in IB, and it detects http links and turns them into hyperlinks."
My experience (at least in xcode 7) is that you also have to unclick the "Editable" behavior for the urls to be detected & clickable.