A few random suggestions. I don't actually know much about Squeak or Scratch, so those might be better options. YMMV, of course.
One way to sort of ease into the idea of instructing-a-computer-so-it-does-things is to make things in a context-free-grammar based system, like: http://www.contextfreeart.org/
I've found some people find it much easier than "real" programming, since it avoids control constructs and such. I personally actually find it a little harder, because I try to think of it in terms of operational semantics, and end up mentally reverse-engineering everything I write into the equivalent C code. I've had good luck introducing non-programming people to it, though; not tried with any kids; mostly computing-interested adults.
Processing is a relatively simple media-computing environment. Based on Java, but highly simplified and oriented towards 2d graphical applets: http://processing.org/
I personally learned on Logo, which I thought was nice. I'm not sure if there are good Logo implementations these days?
One way to sort of ease into the idea of instructing-a-computer-so-it-does-things is to make things in a context-free-grammar based system, like: http://www.contextfreeart.org/
I've found some people find it much easier than "real" programming, since it avoids control constructs and such. I personally actually find it a little harder, because I try to think of it in terms of operational semantics, and end up mentally reverse-engineering everything I write into the equivalent C code. I've had good luck introducing non-programming people to it, though; not tried with any kids; mostly computing-interested adults.
Processing is a relatively simple media-computing environment. Based on Java, but highly simplified and oriented towards 2d graphical applets: http://processing.org/
I personally learned on Logo, which I thought was nice. I'm not sure if there are good Logo implementations these days?