There is a very good book by Geraldine Cotter (a former all-Ireland whistle champion) called I think "Irish Tin Whistle Tutor" and which had an accompanying cassette by Geraldine of all the tunes in the book with guitar accompaniment. It was published by Ossian Publications and may still be available. I used to have a copy but can't lay my hands on it at the moment. I may have lent it to someone and forgotten (all my books go that way). Hope this is of help.

Peace

mcmoo