Ds1 (will be 8 in May) has picked up Asimov's I-Robot off my book shelf and started reading it. He seems to be enjoying it so far (am hoping there's nothing wildly inappropriate in it, has been years since I've read it myself!) - but I do wonder if it's a little old for him.
Does anyone have any recommendations for good science fiction books aimed at children which he might enjoy? I would say his reading level is around Harry Potterish sort of level - it's content is more the issue as while his reading is good, I don't think he's ready for the more mature themes in books aimed at teens.