A School Like Mine, Children Just Like Me, A Life Like Mine, Children Just Like Me: Celebrations – those are the four I have.
Also, when your kids are older we used Hungry Planet:What the World Eats, Material World: A Global Family Portrait, and Man Eating Bugs. (Preview that last one, there was one picture I remember we used sharpie to color shorts on a man – indigenous and not wearing any. Ahem.)