Though _why hasn't given it much love in the past year or so, for a while I was really excited about Hackety Hack. I think the key for most new programmers, especially children who are more than apt to losing interest in things, is instantaneous feedback. That was the really wonderful thing about Hackety Hack: a few lines of code, and suddenly you have something in front of you that does something. There are a few similar applications aimed at things like drawing graphics (one of which, I briefly assisted Nathan Weizenbaum on, Scribble!). Kids simply need positive feedback that they're doing something correct on a regular basis, else there's nothing to keep them interested in the task at hand. What I think the future is for teaching children to program is some sort of DSL built on top of a language with friendly syntax (these would include, arguably, Ruby, Python, and Scheme) whose purpose is to provide an intuitive environment for constructing simple games (say, Tic-Tac Toe, or Hangman).