there is a book about bach flower remedies that is written for children's problems. I have seen it, but I can't remember where. Perhaps you could do a search on the net for it? "bach flower remedies" and "children" or something like that?
I use them too; sometimes I take them for the baby, sometimes I give them directly to the boys. If I think that it is something they are picking up from me, I take it AND give them it too.
I mostly use it intuitively too. Sometimes our oldest will ask for them, I show them all to him and he picks one or two out. Later on I look it up for meaning, and sure enough, it usually matches up with what he is going through.
We always use Rescue Remedy after a nasty fall, after something that shocked the boys or was emotional. I am a firm believer in Flower remedies (not only the Bach flowers though!)