Allow me to repeat myself from another thread:
The only preparation you should be doing before your first year is general reading. Books like Planet Law School give a good idea of what it is like to be in law school. Of course, nothing prepares you for the experience like the experience itself, but at least you won't be walking in blind.
Now, the top 5 reasons on why it is a bad idea to "prepare" or study the law before you go to law school.
#5. You just flat out do not know what to look for. Even if you were to pick up an Examples & Explanations and read it cover to cover (which you won't even need to do once you get in law school) all the legal terms of art will fly past you b/c you've never heard of most of them, perhaps any of them. You don't know what the difference is between Pleading, Impleading, Interpleading or Intervention and unless mom or dad are lawyers with a lot of free time, its just best to wait until you see these concepts within the context of actual cases.
#4. You need to have as much fun as you can BEFORE law school. 1st year is the hardest year of law school. That being said, 1st semester is the hardest semester of law school. You will learn the importance of Time. It will be more valuable to you than you ever thought possible. You will pass up more invitations to parties, send more phone calls to voicemail, and turn down more dates with supermodels than you ever thought possible. A social life is still possible during your first year, but when I say social life I mean you get to go out a couple times per month. This is of course when you figure out that you just have to stop what you are doing and take a break, because there are not enough hours in the space-time continuum to finish the amount of reading that is about to be thrown at you in one semester.
#3. You need as much MONEY as you can get your hands on before law school. If mommy and daddy pay for everything, then discard this reason. If you're not a silver spoon kid, pay special attention to this caveat. For you working people who will be leaving a career, this is especially important. You will be living off of one month's take home for 9 months straight. Start saving now.
#2. You don't want to have to UNLEARN legal conepts. Without the guidance of a law professor, the true meaning of many legal concepts is difficult if not impossible to ascertain. Going back to reason #5, a particular concept itself may not be difficult to understand, but you may be learning it incorrectly. For example, you might read a concept book that tells you about property obligations for tenants. It will more than likely tell you that a property owner is liable for all Invitees that are injured on his icy sidewalk but not for people who are Liscensees. And then you carry this "understanding" with you into law school, where you may or may not discover before the exam that what you read during the summer before your first year USED to be absolutely true, however over the development of case law during the past 50 years, courts have done away with the distinction of liscensee/invitee and just hold land owners liable for anybody who is not a trespasser. But the concept book is not going to tell you that because they are just trying to list all the basic concepts in as short amount of space as possible.
#1. Law School is all about what your Professor wants. In the end, it is your professor who determines your grade. It is the professor who separates the A's from the B's. It is the professor who you have to please, and it is the professor who you have to listen to. You can know every law and legal concept ever created in the US, but if you do not know the type of analysis your professor is looking for, then you're f*cked. This is also why 4.0 students are shocked when 1st year grades are posted b/c many of them get their first B or C ever in their entire academic lives in law school. NOT because it is any reflection of their intelligence as a student. Its because they didn't provide the analysis specific to thier professor. I had 4 finals last semester from 4 different professors with 4 different styles. My property professor just wanted to see both sides of each issue argued. She didn't want an answer b/c she feels there are no answers in the Law, just arguments. My torts professor wanted a strong analysis for one side, discounting the claims that the other side might make, with a definite answer at the end. Now imagine if you did the exact same writing style for all of your professors. You'd get a report card that looks like the scrolling ticker tape on the stock market.
Since you have no idea who your professors are, or more importantly, what areas they want to focus on and how they want their exams written, it is d**mn near pointless to spend the time during your summer trying to prepare for anything. Another 1L's property professor harped on the Rules Against Perpetuities for 2 classes, my professor talked about that mess for 2 minutes and moved on. Its all subjective.
Our advice on the summer before 1L... Make lots of money, party till 3 am every night, have lots of sex, drink lots of alcohol, take a vacation in Hawaii and go watch the sunset or something like that. Don't be one of these dillusioned cats who thinks that learning how to brief a case in June is going to make a d**mn bit of difference come August.