What are some very good courtroom drama movies ?
Erin Brockovich, A Few Good Men, and really any of the John Grisham books that were turned into movies (The Client, Pelican Brief, etc...).
The Runaway Jury
Some of the best courtroom drama movies include classics such as, "12 Angry Men", "The Verdict", Anatomy of a Murder", among many other classics. See http://crime.about.com/od/books/tp/movies_court.htm. Other interesting courtroom drama movies include "Paradise Lost" and "TO Kill a Mocking Bird". See also http://www.franksreelreviews.com/shorttakes/reelrant/franksrant0703b.htm.
And justice for all, a few good men, the jagged edge, primal fear, a few good men, witness for the prosecution