A number of sites can assist you in finding academic job openings.  For U.S. academics, the main one is the AALS, but the others can be useful too.

Association of American Law Schools (AALS)
The clearinghouse for applications to enter law school teaching in the United States. It runs a faculty recruiting conference each fall (popularly known as the "meat market") and provides a collection of valuable information on its faculty recruitment page. This is the best place to start your research into the law teaching business. It also contains links to all member law school pages, permitting your easy access to the web page for most faculties of your likely interest.

Academic Careers Online

Higher Ed Jobs

American Bar Association Career Counseling

The Chronicle of Higher Education job list

Law Crossing
The "largest collection of active legal jobs in the world."

JURIST Canada
A list of job openings, selected fellowships and special opportunities at Canadian law schools, or of interest to Canadian law teachers.

JURIST Australia

Andy Jones has compiled Resources to Aid in the Academic Job Search. These resources are not specific to law schools.