What a wonderful world
Cobra - 585

Still many improvements to be made

class P
    def main
        i='I see '
        f='s of '
        w=' I think to myself\nWhat a wonderful world'
        a='\nAnd[w]'
        t=' the '
        s=' sayin\', "'
        print "[i]trees of green, red roses, too,\n[i]them bloom, for me and you[a].\n\n[i]skie[f]blue, and cloud[f]white,\nThe bright blessed day,[t]dark sacred night[a].\n\nThe colors of[t]rainbow, so pretty in[t]sky,\n are also on[t]face[f]people going by.\n[i]friends shaking hands,[s]How do you do?\"\nThey're really[s]I love you.\"\n\nI hear babies cryin'. I watch them grow.\nThey'll learn much more than I'll ever know\nAnd[w]\n\nYes,[w]"