In my ongoing search for Korean children's books for my husband to read to my daughter, I came across The Milet Picture Dictionary on Amazon. It includes all the basic categories of vocabulary a beginning language-learner needs, like words for food, clothes, parts of the body and furniture. The art is brightly-colored and impressionistic, and each picture is labeled in English and hangul, so either of us can read it with her.
If you've come across any great Korean-language resources for kids, please pass them along.
--Weigook Saram