How to de-indoctrinate children effectively but kindly?

I don't think it would be a good idea to de-indoctrinate a child via indoctrination via Atheism. A better approach, I think, would be firstly to help them understand that people hold differing opinions and you just happen to hold different opinions than them. Telling them THERE'S NO GOD is an order basically and is indoctrination in itself; the parents before you said THERE IS A GOD so you're just confusing the brats if you do so. If you really REALLY feel the need to push your views upon them, then just provide the foundation for a secular lifestyle rather than a full-blown Atheist one so when they're older they have a relativley less biased foundation to base a religious following upon. One love, bredren.