Here's the summary from the Bloomsbury Winter 2009 catalogue (it comes out January 2009):
After her boyfriend dumps her for her older sister, sophomore Savannah Delano wishes she could find a true prince to take her to the prom. Enter Chrissy (Chrysanthemum) Everstar: Savannah’s gum-chewing, cell phone–carrying, high heel-wearing Fair Godmother. Showing why she’s only Fair—because she’s not a very good fairy student—Chrissy mistakenly sends Savannah back in time to the Middle Ages, first as Cinderella, then as Snow White. Finally she sends Tristan, a boy in Savannah’s class, back instead to turn him into her prom-worthy prince. When Savannah returns to the Middle Ages to save Tristan, they must team up to defeat a troll, a dragon, and the mysterious and undeniably sexy Black Knight. Laughs abound in this clever fairy tale twist from a master of romantic comedy.
Charlotte of Charlotte's Library has already reviewed it and says "This is a great romp through the cliches, pitfalls, bitter realities and ultimate romantic triumphs of fairy tale land. I'd give this one to anyone who loved Gail Carson Levine's Ella Enchanted, or Sarah Beth Durst's Into the Wild."
Author Janette Rallison also has JUST ONE WISH coming out in March 2009 from Putnam and that one is in my TBR pile. I can only hope MY FAIR GODMOTHER will soon join it!