Creating an "art ledge" in your child's room, or any room for that matter is super easy. All you need are long pieces of wood trim from your local hardware store, a hammer, and some nails. For our son's room the length of the wall was about 11 feet long, so we bought two 8' pieces and cut one down with a saw.
Once the pieces of trim are cut to the length of your wall, you should prime and paint them before hanging. We used a level to make sure it was straight then nailed the trim directly to the wall. This will leave holes in your trim, so you can fill them with some Patch and Paint and then paint over the holes.
We have to do a repair where our trim connects as you can see in this photo below one piece sticks out a little bit. Need another nail pronto. :) Also, a safety tip for you. You can try to use velcro to attach your frames to the wall, ,but if you use a humidifier in your child's room, the velcro can come loose and your frames can fall. So I actually bought picture hanging mounts and then hung each frame from a nail. They still look like they are sitting on the ledge but are securely attached to the wall. Can't be too careful in a child's room.
This makes such a great way to display your children's art or their favorite prints. My kids love seeing a wall of fun in their room and there's still a little room left to add more frames. To see more pics of the boy's room click on "house tour" above.