Barbara, every now and then, something comes up that is useful to an old post, and thanks to the new handy-dandy search by Max, I was able to find this old thread and give you the tune that you asked for back in September of 98.

While exploring Benjamin R. Tubb's site this evening, I stumbled across a midi for Little Boy Blue the same tune as used by John McCormack and The Irish Rovers. Tubb's music of the 1800s page You'll find it under 1891, composed by Ethelbert Nevin, 1862-1901. Interesting to note that Field wrote the poem in 1888, and Nevin put it to music just three years later.

Do check out the rest of his site as well, there is much to be enjoyed there.