Drag N' Drop

I'm looking for similar functionality to Interface Builder. Specifically, the Draggin' and Dropping of Elements onto the Screen. The "Screen" in this case is a UIScrollView, and the element is a UIButton.



More Details:
I have an UIButton on the Screen, And when I drag inside it, I want a button to spawn, and the button to remove itself from the view when the user drops it into the UIScrollView. If the user doesn't drop it within the bounds of the scroll view, then it will remove itself from the scene.



Hopefully this isn't to hard to understand, it's just like on mac os when you drag your items on the desktop to another place on the screen.