The Collaborative International Dictionary of English v.0.48:

orchestrate \orchestrate\ v. t.
   1. to write an orchestra score for; -- of a musical
      composition.
      [WordNet 1.5]

   2. To be the chief coordinator of (an activity requiring
      action by more than one person); to organize and
      coordinate.

   Syn: mastermind, engineer, direct, organize.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

orchestrate
    v 1: write an orchestra score for
    2: plan and direct (a complex undertaking); "he masterminded the
       robbery" [syn: mastermind, engineer, direct,
       organize, organise, orchestrate]

Moby Thesaurus II by Grady Ward, 1.0:

21 Moby Thesaurus words for "orchestrate":
   adapt, arrange, blend, compose, harmonize, instrument,
   instrumentate, integrate, make an adaptation, melodize, musicalize,
   put to music, score, set, set to music, symphonize, synthesize,
   transcribe, transpose, unify, write