Finding time to produce scholarship while working full-time as a lawyer can be a difficult challenge. Increasingly, law schools offer one or two-year fellowships that afford prospective candidates an opportunity to research, write, receive mentoring from senior faculty, and soak up the atmosphere of a law faculty. Some of these carry teaching obligations (which itself can be a valuable experience and an aid in obtaining a full-time position, provided you get your writing done). Below is a partial list.
Chicago: Bigelow Program
Columbia: Academic Fellows, Associates Program, Center for Reproductive Rights-Columbia Fellowship, Columbia Law Review Milligan Fellowship
Georgetown: Fellowships
Harvard: Fellowships, Climenko Fellowship, Visiting Assistant Professor
NYU: Furman Fellowship Program, Lawyering Program, Furman Center Fellowship (third on list at link)
Northwestern: Visiting Assistant Professors and Fellows
Stanford: Legal Research and Writing Program
U. Texas at Austin: Emerging Scholars Program
Yale: Ruebhausen and Ribicoff Fellowships