Bridget, another resource might be a clarinetist named Billy Novick, a good friend of my sister's in Lexington, Mass. He recorded several albums of traditional and jazz music in the 70s with an outstanding fingerstyle guitarist named Guy Van Duser. They have an album called The New Pennywhistle Songbook (or something like that) on which Billy plays amazing Irish traditional and jazz pennywhistle. I just saw Billy two weeks ago (at my nephew's Bar Mitzvah) and he's mostly playing jazz, film scores, and the like, but I'm sure he could give you tips on playing Celtic music on clarinet, good keys, fingerings, etc. If you're interested I can get his snail or email address for you. Good luck with the band.

Aloha,
Mark