Scholastic has something alled thoer Book Wizard which is supposed to help you find different books on similar themes. For example I'm reading Gordon Korman's exciting On the Run series to some ESOL fourth graders. The books are a little vocabulary rich for hem, but the "book wizard" recommended Braouer's Sewer Rats and Harris' Undercover Girl series for similar action/mystery on an easier reading level.
Check it out here.
