start with www.vault.com or www.jd2b.com Take a look at their message board. You will get some info. I know for a fact that there are ranking sites, starting with the USNWR site. Basically, you've got your Harvard, Yale, Stanford,Chicago,Michigan, Georgetown, Penn, Virginia, Northwestern in the top. Berkeley is around 17 and USC is in top 25. I was looking at them about 4 months when I was trying to decide between Law or MBA. Since I am not much of a wordsmith now, I decided to leave that degree for another time. Just start studying for your LSAT rather early. Good luck.
Forgot to add NYU and Columbia to the top 10. Duke, UCLA, Vanderbilt, UNC(Chapel Hill) and Emory have good but regional reputations as well. Check out this site: http://www.lawschool100.com
The ABA and virtually every law school dean put out a letter a few years ago saying that law school rankings are meaningless. Right. But if you want to make a ton of money, DON'T go to the University of New Mexico instead of Stanford! (Though the education at each is very similar.)