Tuatha de Danann's "A Song for Oengus". Unfortunately, the only clip on YouTube is a guitar solo later in the song.

http://www.youtube.com/watch?v=mVWSkImI09o

It is available on iTunes, tho.

In comparison, I'll put up the other song of their's which I was looking as using as a ring tone: "The Oghma's Rheel"

http://www.youtube.com/watch?v=BnR7z...eature=related