There are already plenty of apps and online sites that can teach your kids the basics of programming. Robots such as the meeperBOT 2.0 can also help. This is an app controlled robot with a brick compatible chassis. It comes with 3 drive modes and can even follow you using your Bluetooth signal.
The meeperBOT comes with a drag & drop interface for simple programming. Users can program up to 8 bots from the same program. The Meeper controller app is available for iOS and Android devices.[where to get it]