Here. It's basically a precis of the arguments from Tamanaha's book. It's a somewhat eclectic group of signatories (even including the person memorably described by Paul Horwitz as "essentially a journalist moonlighting as a law professor," but that's the nature of these letters, one often doesn't know who else is signing--Dick Posner told me Paul Carrington, former Dean at Duke, sent it to him, and he thought Carrington was one of the authors, which may be.) Besides Judge Posner, notable signatories include my former colleague Gerald Torres, a past President of the AALS, Richard Epstein, Lawrence Friedman, Geoffrey Hazard, and Dean Dan Rodriguez from Northwestern (who will be President of the AALS this coming year). It's pretty sensible, and hopefully the ABA will follow the main theme of the advice, which is less regulation, and thus more diversity, in legal education.
ADDENDUM: As one of the more notable signatories wrote me, "The presence of one person’s name on the statement about the costs of legal education almost caused me to ask that mine be removed." But the issue is, obviously, more important than one individual.