kaplan's and princeton's books are simulated exams. they'll give u questions they believe will show up on the test. they're usually not actual questions.
then again, i'm assuming it's a lot like the MCAT.
for a fee, actual past MCAT exams are available online; i dunno if the PCAT has a similar thing going on
the kaplan and princeton books will give u a good overview on the material, but i doubt they'll give u a good grasp on the styles in which the questions are asked