Rhuby, found this post on the eMule Poetry Archives:

>If it is information that is wanted about the poem, I can tell you this much. I first came across it a book called the Nation\'s Favorite Poems published by the BBC. ( ISBN 0 563 38782 3) This is what it had to say.

\"Outside the competition, the unexpected poetry success of the year from the Bookworm\'s point of view was an anonymouis work which featured in a piece on war poetry. \'Do not Stand at my Grave and Weep\' was left in an envelope for his parents by Steve Cummins, a soldier killed on active service in Northern Ireland, to be opned in the event of his death. It provoked an extraordinary response. The requests for copies started coming in almost immediately and over the following weeks the demand rose to a total of some thirty thousand. It was thought at first that the soldier himself had written it, but this was not the case. Claims were made for nineteenth centry magazines and the prayers of Navaho Indian priests, but in the end its origins remain a mystery. In some repsects it became the nations\'s favorite poem by proxy and, despite it being outside the competition , we have decided to include it here, in prime, first past the post, poll position.\" <

there's also some attribution to a Mary Frye in 1932, but her work would have to be an adaptation since the poem appeared much earlier. (be back with that in a minute)