Painting Help?

So I scanned this picture:
to my computer and I want to color it but I don't know what program to use. Which program would be best for coloring these kind of pictures?? Also I have Photoshop CS4 and I don't know how to make the brushes color inside the lines. I've done it before but I forgot how to do it :P would someone please tell me how to?
P.S. I didn't know if this was the correct forum to put it in so if I put it in the bring place will a mod please move it? Thanks! ^^

huh ?

it'd be kinda hard to use paint bucket on that because there are so many breaks in the lines.. however you could cut off the breaks with the paintbrush and w/e colors you plan on using