Haha - Im afraid there is no (or atleast that I know of) Tutorial for creating something like this specifically.
However, there are tons of PS and Gimp Tutorials ;P
aside from knowing how skeletal animation works, and that you have to break down your charackter into seperate limbs, graphics what so ever, im afraid theres just learning to draw xD
for starters id recommend getting yourself a small wacom bamboo tablet or something the like (should be not more than 50 - 60 bugs) and it gets you a long way when doing digital art (personally i had bad experience with noname tablets)
and than when starting a new project, I usually start off by looking at other games and their styles, what I/we like about this style specifically and than mimic and combine aspects.
copying is a good way to get started =)
