Dragging an image on top of an image from the camera...

[pyroblue]

Im just diving into creating my first app (Read through an ObjC book and an iPhone dev book) - but im having difficulties figuring out where to begin.

i basically wanna create something for my kids so they can take a photo and drag something like a funny hat or something else stupid ONTO the photo...

i know how to access the camera and photo library, but how would i go about letting them select static images to drag around and place onto the 'canvas'?

any nudge in the right direction would rule...

thanks!!