I studied with Kaplan, and I don't think it was worth the $$. I have friends who used Powerscore and Blueprint and had much better results. If you have the money, you should definitely take an LSAT class. If you prefer to study on your own, The Powerscore Bibles are a great way to get started.
Early in your studying, you should mostly do untimed sections until you get the basic concepts down. The LSAT is all about reprogramming your brain. Taking it slowly at first will definitely help you get a better grasp of the concepts. I'll forward you a good discussion on LSAT prep that I thought was right on the money.
Best of luck and let me know how it goes.