Hi everyone-
I just stumbled across this board this afternoon while looking for something like it, and I am glad I did. 
Anyway I am a classically trained flute player who has just bought her first two whistles (a sweetone and little black whistle- both of which I have been informed are good for a beginner)- I’ve played flute for 14 years (with forays into saxophone and marimba) and a few weeks ago some friends of mine suggested to me that we form a little Irish band (they are a bunch of fiddle and guitar players) and they wanted me to learn the tin whistle. SO I have ordered my whistles and am waiting for them to arrive, and I was wondering if anyone has any recommendations of good whistle songbooks- bear in mind that I already read music really well, so i don’t need one of those total beginners tutorial things- but i would like recommendations on some nice fat songbooks with lots of fun music i can learn.
thanks
-Angela
What tunesbooks you would find helpful depends on the style of music you would like to play. If it is Irish traditional music, then part of the challenge will be to understand the idiom. Consult Brother Steve’s page, particularly his musings on classically trained musicians. (The link is in the link’s section).
As a tunebook I recommend that you get L.E. McCullough’s 121 Favorite Session Tunes, with CDs. Since the technique will be easy for you, I suggest you learn them all by ear: probably the best way to get into Irish music. It’s available at http://www.homespuntapes.com.
You might also consider L.E. McCullough’s Tinwhistle Tutor, to learn Irish ornaments. You wouldn’t want to be caught in a session playing a mordant for a roll. 
Good luck.