Pride and Prejudice and Zombies is, well, just that. The classic Regency drama is liberally sprinkled with blood-thirsty zombie horror in a monster-lit mash-up. It's the first novel of Seth Grahame-Smith, recently published in April '09. Letting brain-eating zombies loose through 19th century English countryside does sound like a great idea at first, but once you get over the novelty of it all, the book somewhat loses its appeal. The actual plot of PPZ is faithful to the Austen original (she's credited as the co-author), where Elizabeth is rather far-fetchedly (even for a Regency zombie novel) a ninja, of sorts. Obviously it's best to have actually read Pride and Prejudice before this book, to give it some perspective, which is shamefully not the order that this noder has done things in.
If you're a lazy reader, yet interested, don't worry: there is already a film in the pipeline, and you certainly embody its target audience.