Mary mentioned Suo Gan a Welsh lullaby and a beautiful one. You can hear it as a midi (with all the limitations of that format) here:
It also appears on Charlotte Church's first CD (at too fast a tempo for my taste) and is sung at the beginning of the movie "Empire of the Sun". If you're interested (it's in the public domain) e-mail me at:
and I'll e-mail you English lyrics and a phonetic version of the Welsh lyrics.