I seem to be progressing with Lilypond. Here's Felix Mendelssohn's Wedding March from "A Midsummer Night's Dream" - the output's viewable at https://dl.dropboxusercontent.com/u/425499/wedding_march.pdf

wedding_march.ly

\version "2.16.2"
\header {
  title    = "Wedding March"
  composer = "Felix Mendelssohn"
}

dfnat = \markup \concat \vcenter { F \natural D \natural }
dfshp = \markup \concat \vcenter { F \sharp   D \sharp   }
cshp  = \markup \concat \vcenter { C \sharp              }
cfswp = \markup \concat \vcenter { C \natural F \sharp   }
dshp  = \markup \concat \vcenter { (D \sharp)___         }

harpRight_mainTheme_chords = \relative c'' {
  < c e fis c' >2 < b dis fis b >4. < b dis fis >8 |
  < b dis fis a >4( < b e g >) < a d f >_\dfnat < a d > |
}

harpRight_mainTheme_sufA = \relative c'' {
  \phrasingSlurDown {
    c2(\startTrillSpan \grace { b16[\( c] } d4\))\stopTrillSpan g,8.( d'16 |
  } \phrasingSlurNeutral 

  < g, c e >4) c,8 e g[ c e_\dfshp g] |
}

harpRight_mainTheme_sufB = \relative c'' {
  \phrasingSlurDown {
    c2(\startTrillSpan \grace { b16[\( c] } e4\))\stopTrillSpan d8. e16 |
  }
}

harpRight_mainTheme = {
  \harpRight_mainTheme_chords \harpRight_mainTheme_sufA
  \harpRight_mainTheme_chords \harpRight_mainTheme_sufB
}

harpLeft_mainTheme_chords = \relative c' {
  < a c e fis >2 < a b dis fis >4. < a b dis fis >8 |
  < a b dis fis >4( < g b e >) < f a d > < f a d >  |
}

harpLeft_mainTheme_sufA = \relative c' {
  < g c e >2( < g b f' >4) < g b f' >( |
  < g c e>) c,8 e g[ c e g]           |
}

harpLeft_mainTheme_sufB = \relative c' {
  < g c e >2( < g c e >4) < g b f' > |
}

harpLeft_mainTheme = {
  \harpLeft_mainTheme_chords \harpLeft_mainTheme_sufA
  \harpLeft_mainTheme_chords \harpLeft_mainTheme_sufB
}

harpRight = \relative c'' {
  s2.^\markup { \harp-pedal #"v--|-v--" }
  \times 2/3 { c8 c c } |

  \repeat unfold 2 { c2. \times 2/3 { c8 c c } | }

  < c e >4 \times 2/3 { < c e >8 < c e > < c e > }
    < c e >4 \times 2/3 { < c e >8 < c e > < c e > } |

  < c e g >4 \times 2/3 { < c e g >8 < c e g > < c e g > } < c e g >4
    < c e g> |

  \repeat volta 2 { \harpRight_mainTheme }

  \alternative {
    \relative c'' {
      < g b d >2 < g c >4 \times 2/3 { c8 c c } |
      c4 \times 2/3 { e,8 g c } e4 \times 2/3 { g,8 c e } |
      < c e g >4_\dfshp \times 2/3 { < c e g >8 < c e g > < c e g > }
        < c e g >4 < c e g > |
    }

    \relative c'' { < g b d >2 < g c > | }
  }

  \repeat volta 2 {
    < g c >2 < g c >4. < g c >8 |
    < g c e >4( < f b d > < f b > < f g >) |
    < e g >4. < e g c >8 < e g c >4. < g c e >8 |
    < g c e >4( < f b d > < f b > < f g >) |
    < e g >4. < g c e >8 < g c e >4. < c e g >8 |
    < c e g >2( < a d f >4) < a c e > |

    <<
      \relative c'' { d4 cis8._\cshp e16 d4_\cfswp a8. cis16 }
      \\
      \relative c'' { a2 a4 d, }
    >>

    < d, g b >4 < b' d g >  < a d a' > < b d b' >_\dshp |

    \harpRight_mainTheme
  }

  \alternative {
    \relative c'' { < g b d >2 < g c > | }

    \relative c'' {
      < g b d >2 < g c >4 \times 2/3 { c8 c c } |
      < f, a c >4 \times 2/3 { < f a c >8 < f a c > < f a c > }
        < a c f >4 < c f a > |
      < c e g c >1
    }
  }

  \bar "|."
}

harpLeft = \relative c' {
  s2. \times 2/3 { c8 c c } |

  \repeat unfold 2 { c2. \times 2/3 { c8 c c } | }
  \repeat unfold 3 { c4 \times 2/3 { c8 c c } }
  c4 c |

  \repeat volta 2 { \harpLeft_mainTheme }

  \alternative {
    \relative c' {
      < g b f' >2 < g c e >4 \times 2/3 { c8 c c } |
      c4 \times 2/3 { < c e >8 < c e > < c e > }
        c4 \times 2/3 { < c e >8 < c e > < c e > } |
      < g c e >4 \times 2/3 { < g c e >8 < g c e > < g c e >8 }
        < g c e >4 < g c e > |
    }

    \relative c' { < g b f' >2 < g c e > | }
  }

  \repeat volta 2 {
    < c e >2 < c e >4. < c e >8 |
    <<
      \relative c' { e4( d < b d > b) }
      \\
      \relative c' { g1 }
    >> |

    < g c >4. < g c >8 < g c >4. < g e' >8 |
    <<
      \relative c' { e4( d < b d > b) }
      \\
      \relative c' { g1 }
    >>

    < g c >4. < c e >8 < c e >4. < c e g >8 |
    < a c e g >2( < a d f >4) < a c e > |
    <<
      \relative c' { < c d >4 cis8. e16 < c d >4 a8. c16 }
      \\
      \relative c { f2 fis }
    >>

    < g b >4 < g b d > < fis a d > < g b d > |

    \harpLeft_mainTheme
  }

  \alternative {
    \relative c' { < g b f' >2 < g c e > }

    \relative c' {
      < g b f' >2 < g c e >4 \times 2/3 { c8 c c } |
      < f, a c >4 \times 2/3 { < f a c >8 < f a c > < f a c > }
        < f a c >4 < f a c f > |
      < c, g' c e >1
    }
  }

  \bar "|."
}

\score {
  \new PianoStaff <<
    \new Staff = "harpRight" {
      \clef treble
      \key c \major
      \time 4/4

      \harpRight
    }

    \new Staff = "harpLeft" {
      \clef bass
      \key c \major
      \time 4/4

      \harpLeft
    }
  >>
}