two useful ones are richard montauk's "how to get into the top law schools" and anna ivey's "the ivey guide to law school admissions"
I agree, especially about the second one. I would also add "Law School Confidential" to the list. As well as a book with a bunch of good "resume buzz words" for any kind of work you've done. Then look on the Harvard site, they have some links to what your law school resume should look like (which is different than your work resume).
I also picked up a book or two about "how to write law school personal statements" -- any of these will do. You won't be using them so much to guage what a good PS looks like, but to get the juices flowing in your memory about the types of things you could be writing about. After reading a few, I found myself thinking - gee, I never would have thought to write about that, but I have similar experiences!