Okay...here's what I've found/remembered:
I remembered finding this information through the Deloggio Achievement Program site a few years ago and vaguely remembered something about Boalt. So I went back to that site and, sure enough, Boalt is the school that started this. The chart either used to be on Deloggio's site or Boalt's site...however, now I don't see it on either. But it's called the Berkeley System--some schools do it, some don't and some do it differently than Boalt does (like, I know I remember reading that Penn allegedly adds .2 to the GPA from certain schools...some schools also do it even for "grade inflation" schools).
So check this site:http://www.deloggio.com/homepage/faq/academic/college.htm
A few things on this site: I wouldn't say all schools view your grades as worthless if your school's mean is a 3.2+, especially if your school is top 20. Also, in Montauk's book "How To Get Into the Top Law Schools" the "feeder" schools to Columbia (and probably many other top law schools) are listed as (in order from the most to the least) Yale, Columbia, Harvard, Brown, Penn, Stanford, Berkeley, Dartmouth, Princeton, Cornell, Michigan, UT-Austin, UCLA, NYU, Duke, UVA, Brigham Young, Barnard, Emory, Wellesley, Georgetown, Northwestern, Rice and Smith. I'm pretty sure a lot of these schools have means above 3.2 (Emory's is a 3.3, for example). I think if your school is one of these schools, then you probably get a boost in admissions at most schools (as Deloggio indicates feeder schools do). They will probably look more at how well students with your GPA from your undergraduate school have done at their law school.