If you like the Sisters Grimm series, here are some other books you might enjoy reading.
Beastly by Alexandra Flinn
A modern retelling of "Beauty and the Beast" from the point of view of the Beast, a vain Manhattan private school student who is turned into a monster and must find true love before he can return to his human form.
Beast by Donna Jo Napoli
Elaborates on the tale of "Beauty and the Beast," told from the point of view of the beast and set in Persia.
Goose Chase by Patrice Kindl
Rather than marry a cruel king or a seemingly dim-witted prince, an enchanted goose girl endures imprisonment, capture by several ogresses, and other dangers, before learning exactly who she is.
Once Upon a Marigold by Jean Ferris
A young man with a mysterious past and a penchant for inventing things leaves the troll who raised him, meets an unhappy princess he has loved from afar, and discovers a plot against her and her father.