Funny thing about the sprites was when i first started, he was originally done completely in vectors in Flash.
This is what he originally looked like.
<img src="https://lh5.googleusercontent.com/-Xt50eUX5ebY/UWZPMsMCs0I/AAAAAAAAAVQ/vQdrOjKTByY/s512/washedupheroCARTOON.png" border="0" />
I eventually thought it was too simple looking and took each piece and painted them in Photoshop, I think painting the pieces didn't take very long actually, I think around a day.
I just learned my skills on my own, I didn't get any special training/ schooling. I just practiced a lot during high school and my short time in college, I Did some co-op at a game publishing company and I learned a few tricks from an Illustrator over there. LoL I don't think there is a name for the art style this is just what comes out of my hand naturally.
I haven't heard of spriter until a few days ago, I haven't ever used it before. It seems neat I may tinker with it to see if I can pull off anything interesting.