I don't like the tutorials given off of most websites...
One of the most popular books I know of teaching you how to draw is Drawing on the Right Side Of the Brain, this book is one of the most popular choices for some reason.
http://www.amazon.com/New-Drawing-Right-...0874774241
However, my suggestion is learn first to draw from life. I think that will teach you best how to understand drawing abstract, cartoony, or whatever, as it is the basis for all the other stuff. You can find models online, or start actually going out on your own and looking for stuff to draw.
I guess if you do some reading and them some practice, you can get pretty darn far, and probably make better stuff than the artworks you posted