The Wizard, the Witch, and Two Girls from Jersey, by Lisa Papademetriou (Razorbill 2006)(On sale date 18 May 2006).
Veronica Lopez is smart, an avid fantasy reader, and not altogether unattractive. Heather Simms is beautiful, shallow, selfish, vain, and not as dumb as you'd think. The evening before they have to deliver a book report on the classic The Queen of Twilight (Veronica's favorite novel), they are zapped into its pages through the good offices of a malfunctioning bookstore Universal Product Code reader.
All they have to do, Veronica figures, is work their way through the plot (which she knows intimately), and then the wizard Strathorn can send them back home. Things begin to go badly from the start, when they accidentally, er, expunge the Princess Arabelle, the prophesied "One," who is supposed to save the land of Galma from the evil Queen of Twilight. Throw in a talking and lascivious squirrel, a bakery elf in exile, a magic-less wizard, a whole bunch of other stuff that's not in The Queen of Twilight, and they may not survive, let alone save Galma and get back home.
This novel is hilarious -- a wonderful romp that pokes fun at the conventions of high fantasy and high school. Highly recommended.