Fill, Fill A Rún

Sopranno Regina Nathan's page has a 32 second sound clip of Fill, Fill A Rún.

The song is also on a Windham Hll recording 'Celtic Requiem' (link is to amazon.com's page on the CD). Mary McLaughlin is featured on the CD, but I don't know if she's the one who sings this song. (CD is by 'various artists'.)

I didn't come across any full length MP3s, but I hope this helps in your search.