Where to download the user guide
www.usa.canon.com has a download section for manuals, drivers and software — this is the link.
The Canon EOS 1D Mark III White Paper
This 63-page PDF is courtesy of Canon USA, and RobGalbraith.com has written up a nice summary of the contents therein, and provided a download link. Click here to read all about it.
The EOS-1 Class Digital SLR Document
This 1.1 MB PDF file is dated October 19th, 2004 and is written by Chuck Westfall and hosted at Canon USA — click here to download the document.
It describes how to get the most out of your 1D series camera, with a wealth of tips and techniques on camera handling, settings and getting maximum image quality from it.