The books mentioned previously are excellent resources.  I would
like to add:  "Automatic Organs - A Guide to Orchestrions, Barrel
Organs, Fairground, Dancehall & Street Organs Including Organettes"
by Arthur W.J.G. Ord-Hume.  It is a thorough exploration of the history
of these machines.  Pay particular attention to the following chapters:

Chapter 16 - Mechanical Organ Preservation, Conservation & Restoration,
Chapter 17 - Pneumatic Organ Preservation, Conservation & Restoration,
Chapter 18 - Living with the Automatic Organ - Care & Maintenance.

The book is available through SchifferBooks.com but the only book to go
into such detail.  [ try this tiny url: http://tinyurl.com/mgm8gnt  --Jody ]

Also note that Schiffer Books publishes "Acanthus Carving & Design"
by Bob Yorburg.  There are numerous pictures of organ facades for those
interested in carving their own pieces.  There is a step-by-step
approach to carving explained.

Bob Yorburg
http://www.bobyorburg.com/