The Book of the Week in the "Style" section of the Washington Post is Michael Buckley's The Sisters Grimm.
Written for kids ages 9-12, The Sisters Grimm tells the tale of Sabrina and Daphne Grimm, two foster kids who end up with "Grandmother." Crazy adventures ensue when "grandmother is kidnapped by a giant, and some police officers turn out to be the Three Little Pigs." Two volumes are out now--The Sisters Grimm: The Fairy-Tale Detectives and The Sisters Grimm: The Unusual Suspects with a third to be released in the spring.
These are on my must-purchase list.