In my opinion there is NO substute for a live instructor and class training for the beginner. However there ARE many materials to enhance or supplement your live training and for advanced training of the experienced student.
There are a number of resources for "home study" or "distant learning" material including:
quick review manuals
quick review videos
in-depth study manuals
in-depth video training
complete home study courses
(which includes both video and written material
as well as video testing for rank).