Here's a list of helpful websites I've found just starting to research the process:
http://orthocj.com/2000/06/a-patients-guide-to-orthognathic-surgery/ - a patient's guide to orthognathic surgery
http://doublejawsurgery.com/ - a Canadian man, Graham, had double jaw surgery to correct a severe underbite.
http://mycorrectivejawsurgery.blogspot.com/ - a woman, Stephanie, underwent surgery and detailed the experience
http://survivingjawsurgery.blogspot.com/ - another girl, another underbite experience.
http://patientadvocate.org/ - a website that's super helpful in the appeals process, they have sample letters, steps to filing an appeal, etc.
http://icd9cm.chrisendres.com/ - search I-9 codes to get a better idea about your exact diagnosis (you'll need to get your codes from your surgeon)
https://catalog.ama-assn.org/Catalog/cpt/cpt_search.jsp - search CPT codes for an idea of the procedures recommended by your surgeon (you'll need to get your codes from your surgeon)