Dave Mallinson's tutors are fantastic for a beginner: you don't need to be able to read music and you can get a CD to go with the book.
It starts with easy tunes and gets a little more complicated near the end, they have a notation that corresponds to the holes in the Tin Whistle so you don't need to be able to read music. It is easy to read and clearly set out.
I began to learn the Tin Whistle with these books, Irish, English, Popular and Scottish and I think that they are brilliant. I have gone onto learn how to read music and play different tunes but I still come back to these books. I cannot praise them enough. I wish Mr Mallinson would do one for Breton and American tunes as well.
If you get one and you practice 15 mins per day you will soon be playing tunes and will not regret it.