It's in the Gaelic Resources Database of the Western Isles Council, at www.cne-siar.gov.uk/grd. Click on "Search the GRD" and enter Calum Sgaire or Oran Chaluim Sgaire in the title box.
It's also on one of Mairi Mc.Innes's CD's, either This Feeling Inside or Orosay, and the words are in the sleeve notes. I think it's also in Anne Lorne-Gillies's Songs of Gaelic Scotland and one of the Ceo\l nam Feis books.