tutorials on digitally inking / coloring a pencil drawing

http://designinstruct.com/drawing-illustration/how-to-color-inked-line-art-in-photoshop/

http://www.instructables.com/id/A-great-technique-for-scanning-your-inked-drawings/step2/Edit-your-artwork-and-remove-the-background/

http://design.tutsplus.com/tutorials/quick-tip-preparing-line-drawings-for-coloring-in-photoshop--psd-3273