These pages are the best way to develop the hand eye co-ordination. Holding the color pencil and coloring within the line also involves development of motor co-ordination. It adds to the dexterity of the fingers, improves the concentration too. Such activities being interesting urges the child to complete before involving in a new task, which is good for improving concentration. Creativity with better learning is best achieved by coloring.
Now we have summer cocktail and beach coloring pages for summer, girl under the umbrella is for autumn. Every season is funny if you have a good coloring pages for that.
Occasionally, you'll find official cartoon or TV character sites (such as PBS programs) will make available coloring pages for free to their fans. And there are many other sites that distribute coloring pages of those copyrighted characters. Sounds like dangerous legal ground ...but, surprisingly, I've never heard of any of these sites being prosecuted for copyright infringement. So they'll probably continue to make them available.