Stop motion app for kids?

[rockybalboa]

Can anyone please recommend a stop motion app (preferably for the iPad)? My 6 year old is off school for the time being and I'm looking for ways to keep him stimulated. He is Lego obsessed and loves watching Lego videos people have made on YouTube (which can be problematic as they are often sweary!) and I figured that whilst he's got time to kill he could have a crack at making his own stop motion video using the iPad. There seem to be a few options out there but if anyone.can make any personal recommendations before I pay for an app I would be very grateful.

[Hamper]

You can use an iPad camera, upload to the cloud, download to the PC and use windows movie maker. Then it's free! :)

[rockybalboa]

We are an entirely soul-sold-to-Apple house so Windows movie maker not an option, arrrgh!