Her album Pure has some great songs on it — especially the songs Never Say Goodbye and Who Painted the Moon Black. Beat of Your Heart is quite good too. You can see the lyrics to the songs on this album here.
More samples available on amazon.
There is even a book about her titled Hayley Westenra: World At Her Feet.
See interview of Hayley and clips of her performance in Ulysses, a Iris pub in lower Manhattan New York.