I use an old art school book that was given to me years ago as a reference.
Other wise there is a lot of info online to instruct one for furry art and general
art. Books are nice in that they have a lot of information on their subject.
But the internet can make a good substitute if one doesn't have a lot of
money to buy books.
Many tablets come with basic art programs. They are usually a light version of
a higher priced program. Do a google or yahoo search. There are a few free to
use art programs available online other than gimp.
I use the basic Wacom Bamboo tablet. Nearly all the drawings I have posted
in the last few years were done with it. Drawings before that were with older
tablets. I haven't checked the price lately, but I paid about $65 for mine.
The higher priced versions usually just have some buttons for convenience
of changing options. Otherwise they don't work much if any better for drawing.
Price is generally set by the size of the drawing tablet. I find the smallest one
works fine for me. Some like larger ones, but I found I only used a small part
of the tablet. So I decided why spend money for a large one when I only used
a small part of it.
Remember you can expand your art to any size you want on your monitor. So
the size of the tablet isn't critical unless you just like more room for drawing.
You can set the tablet so it will use all of the monitor screen or a small part of it.