If you are young onset I recommend 'When Parkinson's Strikes Early' by Barbara Blake-Krebs and Linda Herman. It was printed in 2001 so some of the medical info is outdated, but it's still a worthwhile read.
Another book I like is 'The First Year: Parkinson's Disease - An Essential Guide for the Newly Diagnosed' by Jackie Hunt-Christensen.
There also are a couple of organizations with some great free literature you can order:
American Parkinson Disease Foundation (APDF) at http://www.apdaparkinson.org/userND/PublicationOrder.asp
and the National Parkinson Foundation (NPF) at http://www.parkinson.org/Patients/PD-Library.aspx or
(you'll have to copy and paste the links if the hyperlink didn't work).
Life is a dance. Don't sit it out. ---- Jackson H. Brown