The original sketches were done by hand and then scaned into my computer. From here I imported them into "Adobephotoshop CS2" and used the sketches to create assitate like layers. This allowed me to lay the colour beneath the actual image. This way there was less chance of me making a mistake. If you have "Photoshop CS2" and want to try this. You'll need to make a sketch and Scan it. Once you have it open in photoshop, you can adjust the levels (Ctrl + L) to make the black lines apear more bolder. Then enter this combination
Ctrl + Alt + 1 = Ctrl + Shift + I = Ctrl + J. This will leave you with the original image and a layer that will only show the lines with a transparant background. You can then insert layers beneath this to apply colour to your image.
Enjoy creating your own works and hope that this helps you.