Give it a try! Print out a few Christian coloring pages for your kids and see how they respond. It is a great way to keep them thinking about the things of the Lord.
Alternatively, you could use coloring pages as a reward that you give to your child when he or she does something good, like says thank you, gives a compliment, or helps out before being asked. Not only does it reward them by giving them an activity they will enjoy doing, but it also demonstrates to them that it is good to do things that please the Lord.
Local Christian bookstores usually also have individual pages or reproducible coloring books from which you can make copies so that more than one child can color in the same story picture. This is particularly useful if you want to give your Sunday School students something to color while you are teaching the lesson.