Hopscotch was the first app to offer Scratch style programming on the iPad. Recently its had a big update and its even easier to create simple games and animations. You can even make use of the iPad's built in sensors to trigger events which is great if you want to make games that respond to tilt and sounds.
It costs £ Free and is availble for the iPad
Why we like it - Really simple interface with colourful attractive characters make learning block style programming as easy as dragging and dropping.