When i want to color something in photoshop, most of the time I ink it on paper first.

#A#
Sketch out your art and put in as much detail as possible beforehand. When you drawing looks "finished" it is time to begin the inking process.Please note that drawings can be colored in just about any way without inking them. Inking just give it a cleaner look, while pencil will tend look a sketchy, soft look.

#B#
Get a thin liquid pen or ink pen (gel, pilot, whatever is cheap and floats your boat). Slowly start inking your drawing by tracing over your lines. Make smooth strokes and continue them till the end of the line. This will help you avoid jagged art.

#C#
Get an eraser, i prefer white soft rubber erasers which tend to work best. Becareful not to wrinkle or tear your drawing, erase all of the pencil lines. This will make your inking look a bit empty, but fear not, there is still work to be done! I bet you think is finish already eh? ^^

#D#
Line value is the key to a good inking. Thicker lines can be used to show an area in shadow, or an area in the foreground. Once you finish adding thickness to key lines you are all ready to color your image however your heart desires.

and that's the end of your inking tutorial simple eh?