Learning is fun! And Haskell's IO functionality is pretty easy. They teach it in the very first programming course at Chalmers in Gothenburg. It's covered in any introductory Haskell book.
Yes it's covered in any Haskell book - what use would a language book be without covering IO? How far back in the book it comes, relative to other languages, is the telling piece. LYAH has it as Chapter 9, after algebraic data types, higher order functions, functors, and recursion... I note that in the one week introduction I did for my MSc at the University of Oxford, they didn't cover it, considering it to be too much to fit in to the week.
Having taken the rite of passage that is writing my own monad tutorial, I would agree, the concept is both easy and intuitive. Getting it in to your head, however, takes considerably more work than in any other language I've used.
Waiting until chapter 9 isn't so bad when you realize that many professional programmers including myself have been doing this for 20+ years and are still learning the best way to structure effects within a program. What's the rush anyways?
Having taken the rite of passage that is writing my own monad tutorial, I would agree, the concept is both easy and intuitive. Getting it in to your head, however, takes considerably more work than in any other language I've used.