Re: How Rick griffin does it.
Basically, It won't Mather much what you use to draw.
most people use Photoshop.
but you can get the same effect for drawing with free software like:Gimppaint.net
and my favoite free drawing software:Artweaver
Tablets are plentiful, I suggest for a starting person to buy a trust tablet , unless you can find a bamboo somewhere really cheap.
The reason for getting a Trust is that you won't notice the difference that much, only you are a heavy sketch artists (in witch case Bamboo's are more responsive) you might want to spend the extra money.
of course there are more then just those two.