Junie B. Jones is (almost) a flower girl / Barbara Park / 68 pgs.

Six-year-old Junie B. is disappointed to find out that her aunt has asked someone else to be the flower girl at her wedding.  Junie does get the job as "alternate" flower girl, so she practices her walking and petal tossing and trying to be grown up. 
I'm not real crazy about the Junie B. Jones series, but my two girls seem to really enjoy it.  Junie is very hyper and gets in trouble quite a bit.  At least she doesn't get rewarded for her behavior and that's a good way to open up conversations with your kids about etiquette and social behavior.  I especially liked the conversation that Junie's mother has with Junie about why you don't "wish" that someone gets hurt or sick just so you can be happy.  I love it when Children's books talk about compassionate behavior.