There are books on gifted and motivation. Sorry I don't have reccommendations. That's something I want to read at some point.
A Love for Learning is one that I've seen recommended a lot. I've been meaning to get it and probably will soon. It has good reviews on Amazon, but I haven't read it yet.
We've been trying the approach of, "maybe it isn't typical, but that doesn't mean that it isn't normal." Gifted is not abnormal; it is just atypical. Being unusual doesn't mean that there is something wrong with you or you are abnormal.